Nested frequency hopping for data transmission

ABSTRACT

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a discovery reference signal from a base station on an anchor channel. The UE may perform a first random or pseudorandom frequency hopping procedure to identify a plurality of downlink carriers for a first time period. The UE may perform a second random or pseudorandom frequency hopping procedure within the plurality of downlink carriers to select one of the plurality of downlink carriers as the uplink channel for a second time period. The UE may then transmit an uplink communication during the second time period on the selected uplink channel. In some examples, the uplink communication may be transmitted based at least in part on time division multiplexing (TDM) information.

CROSS REFERENCE

The present Application for patent is a Continuation of U.S. patentapplication Ser. No. 16/255,645 by LIU et al., entitled “NESTEDFREQUENCY HOPPING FOR DATA TRANSMISSION” filed Jan. 23, 2019, whichclaims the benefit of U.S. Provisional Patent Application No. 62/623,987by LIU et al., entitled “NESTED FREQUENCY HOPPING FOR DATATRANSMISSION,” filed Jan. 30, 2018, assigned to the assignee hereof, andexpressly incorporated herein by reference in its entirety.

BACKGROUND

The following relates generally to wireless communication, and morespecifically to frequency hopping for data transmission.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform-spread-OFDM (DFT-S-OFDM). A wireless multiple-accesscommunications system may include a number of base stations or networkaccess nodes, each simultaneously supporting communication for multiplecommunication devices, which may be otherwise known as user equipment(UE).

Narrowband communications involve communicating with a limited frequencybandwidth as compared to the frequency bandwidth used for LTEcommunications. One example of narrowband communication is narrowband(NB) Internet of Things (IoT) (NB-IoT) communication, which may belimited to a single resource block (RB) of system bandwidth, e.g., 180kHz. Another example of narrowband communication is enhancedmachine-type communication (eMTC), which may be limited to six RBs ofsystem bandwidth, e.g., 1.08 MHz. NB-IoT communication and/or eMTC mayreduce device complexity, enable multi-year battery life, and providedeeper coverage to reach challenging locations such as deep insidebuildings.

SUMMARY

The described techniques relate to improved methods, systems, devices,or apparatuses that support nested frequency hopping for datatransmission. Generally, the described techniques provide for systemsand methods for selecting an uplink channel for uplink communications. Auser equipment (UE) may receive a discovery reference signal from a basestation on an anchor channel. The UE may perform a first random orpseudorandom frequency hopping procedure to identify a plurality ofdownlink carriers for a first time period. The UE may perform a secondrandom or pseudorandom frequency hopping procedure within the pluralityof downlink carriers to select one of the plurality of downlink carriersas the uplink channel for a second time period. For example, the UE mayrandomly or pseudo-randomly select one of the plurality of downlinkcarriers as the uplink channel, randomly or pseudo-randomly select apermutation of the plurality of downlink carriers and select the uplinkchannel based at least in part on the selected permutation, or randomlyor pseudo-randomly select a primary channel as the uplink channel. TheUE may then transmit an uplink communication during the second timeperiod on the selected uplink channel. In some examples, the uplinkcommunication may be transmitted based at least in part on time divisionmultiplexing (TDM) information.

A method of wireless communication is described. The method may includereceiving, by a wireless device, a discovery reference signal on atleast one anchor carrier, performing a first random or pseudorandomfrequency hopping procedure to identify a plurality of downlink carriersfor a first time period, performing a second random or pseudorandomfrequency hopping procedure within the plurality of downlink carriers toselect one of the plurality of downlink carriers as an uplink channelfor a second time period, and transmitting an uplink communication onthe selected uplink channel during the second time period.

An apparatus for wireless communication is described. The apparatus mayinclude means for receiving, by a wireless device, a discovery referencesignal on at least one anchor carrier, means for performing a firstrandom or pseudorandom frequency hopping procedure to identify aplurality of downlink carriers for a first time period, means forperforming a second random or pseudorandom frequency hopping procedurewithin the plurality of downlink carriers to select one of the pluralityof downlink carriers as an uplink channel for a second time period, andmeans for transmitting an uplink communication on the selected uplinkchannel during the second time period.

Another apparatus for wireless communication is described. The apparatusmay include a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe operable to cause the processor to receive, by a wireless device, adiscovery reference signal on at least one anchor carrier, perform afirst random or pseudorandom frequency hopping procedure to identify aplurality of downlink carriers for a first time period, perform a secondrandom or pseudorandom frequency hopping procedure within the pluralityof downlink carriers to select one of the plurality of downlink carriersas an uplink channel for a second time period, and transmit an uplinkcommunication on the selected uplink channel during the second timeperiod.

A non-transitory computer-readable medium for wireless communication isdescribed. The non-transitory computer-readable medium may includeinstructions operable to cause a processor to receive, by a wirelessdevice, a discovery reference signal on at least one anchor carrier,perform a first random or pseudorandom frequency hopping procedure toidentify a plurality of downlink carriers for a first time period,perform a second random or pseudorandom frequency hopping procedurewithin the plurality of downlink carriers to select one of the pluralityof downlink carriers as an uplink channel for a second time period, andtransmit an uplink communication on the selected uplink channel duringthe second time period.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for receiving a downlink communicationfor the wireless device on a downlink channel of the plurality ofdownlink carriers, where the uplink channel may be different than thedownlink channel.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, performing the second randomor pseudo-random frequency hopping procedure within the plurality ofdownlink carriers may include randomly or pseudo-randomly selecting theone of the plurality of downlink carriers.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, performing the second randomor pseudo-random frequency hopping procedure within the plurality ofdownlink carriers may include randomly or pseudo-randomly selecting apermutation of the plurality of downlink carriers. Some examples of themethod, apparatus, and non-transitory computer-readable medium describedabove may further include processes, features, means, or instructionsfor selecting the uplink channel based at least in part on thepermutation.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, performing the second randomor pseudo-random frequency hopping within the plurality of downlinkcarriers may include randomly or pseudo-randomly selecting a primarychannel as the uplink channel.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, performing the second randomor pseudo-random frequency hopping procedure within the plurality ofdownlink carriers may include selecting the one of the plurality ofdownlink carriers based at least in part on a random or pseudo-randomnumber generator.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, performing the second randomor pseudo-random frequency hopping procedure within the plurality ofdownlink carriers may include selecting one of a plurality of datachannels based at least in part on a random or pseudo-random hoppingpattern.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for receiving, from a base station,time division multiplexing information for the uplink channel.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, the uplink communication maybe transmitted based at least in part on the time division multiplexinginformation.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, the first time period and thesecond time period may be in a same frame.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for performing a third random orpseudorandom frequency hopping procedure within the plurality ofdownlink carriers to select a second one of the plurality of downlinkcarriers as a second uplink channel for a third time period. Someexamples of the method, apparatus, and non-transitory computer-readablemedium described above may further include processes, features, means,or instructions for transmitting a second uplink communication on theselected second uplink channel during the third time period, where thethird time period may be in the same frame.

In some examples of the method, apparatus, and non-transitorycomputer-readable medium described above, each of the plurality ofdownlink carriers may include a resource block.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for receiving, by the wireless device,a second discovery reference signal on the at least one anchor channel.Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for performing a third random orpseudorandom frequency hopping procedure to identify a second pluralityof downlink carriers for a third time period. Some examples of themethod, apparatus, and non-transitory computer-readable medium describedabove may further include processes, features, means, or instructionsfor performing a fourth random or pseudorandom frequency hoppingprocedure within the plurality of downlink carriers to select one of thesecond plurality of downlink carriers as a second uplink channel for afourth time period. Some examples of the method, apparatus, andnon-transitory computer-readable medium described above may furtherinclude processes, features, means, or instructions for transmitting asecond uplink communication on the selected second uplink channel duringthe fourth time period, where the first time period and the second timeperiod may be in a different frame than the third time period and thefourth time period.

A method of wireless communication is described. The method may includetransmitting, by a wireless device, a discovery reference signal on atleast three anchor carriers, performing a first random or pseudorandomfrequency hopping procedure to select a plurality of downlink carriersfor a first time period, identifying an anticipated collision of uplinktransmissions from user equipment (UEs) during a second time periodbased at least in part on a second random or pseudorandom frequencyhopping procedure within the plurality of downlink carriers, andtransmitting time division multiplexing information for the second timeperiod to the UEs.

An apparatus for wireless communication is described. The apparatus mayinclude means for transmitting, by a wireless device, a discoveryreference signal on at least three anchor carriers, means for performinga first random or pseudorandom frequency hopping procedure to select aplurality of downlink carriers for a first time period, means foridentifying an anticipated collision of uplink transmissions from userequipment (UEs) during a second time period based at least in part on asecond random or pseudorandom frequency hopping procedure within theplurality of downlink carriers, and means for transmitting time divisionmultiplexing information for the second time period to the UEs.

Another apparatus for wireless communication is described. The apparatusmay include a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe operable to cause the processor to transmit, by a wireless device, adiscovery reference signal on at least three anchor carriers, perform afirst random or pseudorandom frequency hopping procedure to select aplurality of downlink carriers for a first time period, identify ananticipated collision of uplink transmissions from user equipment (UEs)during a second time period based at least in part on a second random orpseudorandom frequency hopping procedure within the plurality ofdownlink carriers, and transmit time division multiplexing informationfor the second time period to the UEs.

A non-transitory computer-readable medium for wireless communication isdescribed. The non-transitory computer-readable medium may includeinstructions operable to cause a processor to transmit, by a wirelessdevice, a discovery reference signal on at least three anchor carriers,perform a first random or pseudorandom frequency hopping procedure toselect a plurality of downlink carriers for a first time period,identify an anticipated collision of uplink transmissions from userequipment (UEs) during a second time period based at least in part on asecond random or pseudorandom frequency hopping procedure within theplurality of downlink carriers, and transmit time division multiplexinginformation for the second time period to the UEs.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for receiving the uplink transmissionsover the selected uplink channel during the second time period based atleast in part on the time division multiplexing information.

Some examples of the method, apparatus, and non-transitorycomputer-readable medium described above may further include processes,features, means, or instructions for transmitting a downlinkcommunication on at least one of the plurality of downlink carriers,where the downlink communication may include the time divisionmultiplexing information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communicationthat supports nested frequency hopping for data transmission inaccordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system thatsupports nested frequency hopping for data transmission in accordancewith aspects of the present disclosure.

FIG. 3 illustrates an example of a communication sequence in a wirelesscommunication system that supports nested frequency hopping for datatransmission in accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of a communication sequence in a wirelesscommunication system that supports nested frequency hopping for datatransmission in accordance with aspects of the present disclosure.

FIG. 5 illustrates an example of a communication sequence in a wirelesscommunication system that supports nested frequency hopping for datatransmission in accordance with aspects of the present disclosure.

FIG. 6 illustrates an example of a communication sequence in a wirelesscommunication system that supports nested frequency hopping for datatransmission in accordance with aspects of the present disclosure.

FIG. 7 illustrates an example of a communication flow in a wirelesscommunication system that supports nested frequency hopping for datatransmission in accordance with aspects of the present disclosure.

FIG. 8 illustrates an example of a communication flow in a wirelesscommunication system that supports nested frequency hopping for datatransmission in accordance with aspects of the present disclosure.

FIGS. 9 through 11 show block diagrams of a device that supports nestedfrequency hopping for data transmission in accordance with aspects ofthe present disclosure.

FIG. 12 illustrates a block diagram of a system including a UE thatsupports nested frequency hopping for data transmission in accordancewith aspects of the present disclosure.

FIGS. 13 through 15 show block diagrams of a device that supports nestedfrequency hopping for data transmission in accordance with aspects ofthe present disclosure.

FIG. 16 illustrates a block diagram of a system including a base stationthat supports nested frequency hopping for data transmission inaccordance with aspects of the present disclosure.

FIGS. 17 through 18 illustrate methods for nested frequency hopping fordata transmission in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Frequency hopping techniques may be used in connection with NB-IoTcommunications. For example, a base station and associated userequipment (UEs) may perform a frequency hopping procedure to select anumber of data channels for downlink and uplink communications. Forexample, for communications between a base station and three associatedUEs, the frequency hopping procedure may be used to identify threechannels for both downlink and uplink communications.

However, such a scheme may disadvantage one of the UEs. For example, thefrequency hopping procedure may be used to identify three channels forcommunications. The first channel may be assigned for communicationsbetween the base station and a first UE, the second channel may beassigned for communications between the base station and a second UE,and the third channel may be assigned for communications between thebase station and a third UE. However, the second channel may experienceinterference such that communications between the base station and thesecond UE are not possible. In such situations, the second UE cannotreceive downlink communications or transmit uplink communications, andthat entire time period may be wasted from the perspective of the secondUE.

In order to decrease the number of wasted time periods, each UE mayperform a random or pseudorandom frequency hopping procedure within theselected downlink carriers to select an uplink channel. Each UE may thentransmit an uplink communication on the selected uplink channel. In thismanner, even if the UE is unable to receive downlink communications fromthe base station, it may be able to transmit uplink communicationsbecause the uplink channel may be different than the downlink channel.

In some examples, the second random or pseudorandom frequency hoppingprocedure may include randomly or pseudo-randomly selecting an uplinkchannel from the plurality of downlink carriers. In some examples, thesecond random or pseudorandom frequency hopping procedure may includerandomly or pseudo-randomly selecting a permutation of the plurality ofdownlink carriers, and then selecting the uplink channel based at leastin part on the selected permutation. In some examples, the second randomor pseudorandom frequency hopping procedure may include randomly orpseudo-randomly selecting a primary channel.

In some examples, one or more of the UEs may select the same channel asthe uplink channel. In order to avoid a wasted uplink time period due tocollisions from another UE in the same cell, the base station mayprovide time division multiplexing (TDM) information to the one or moreUEs. The one or more UEs may then transmit uplink communications on acommon selected uplink channel based at least in part on the TDMinformation.

Aspects of the disclosure are initially described in the context of awireless communications system. Aspects of the disclosure are furtherillustrated by and described with reference to apparatus diagrams,system diagrams, and flowcharts that relate to nested frequency hoppingfor data transmission.

FIG. 1 illustrates an example of a wireless communications system 100 inaccordance with various aspects of the present disclosure. The wirelesscommunications system 100 includes base stations 105, UEs 115, and acore network 130. In some examples, the wireless communications system100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A)network, an LTE-A Pro network, or a New Radio (NR) network. In somecases, wireless communications system 100 may support enhanced broadbandcommunications, ultra-reliable (e.g., mission critical) communications,low latency communications, or communications with low-cost andlow-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation Node B orgiga-nodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (e.g., macro or small cell base stations). The UEs 115 describedherein may be able to communicate with various types of base stations105 and network equipment including macro eNBs, small cell eNBs, gNBs,relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up only a portion of the geographic coverage area110, and each sector may be associated with a cell. For example, eachbase station 105 may provide communication coverage for a macro cell, asmall cell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-Things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples half-duplexcommunications may be performed at a reduced peak rate. Other powerconservation techniques for UEs 115 include entering a power saving“deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In some cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and a wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In some cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105, or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 facilitates the scheduling ofresources for D2D communications. In other cases, D2D communications arecarried out between UEs 115 without the involvement of a base station105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1 or otherinterface). Base stations 105 may communicate with one another overbackhaul links 134 (e.g., via an X2 or other interface) either directly(e.g., directly between base stations 105) or indirectly (e.g., via corenetwork 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one Packet Data Network (PDN) gateway (P-GW). The MME may managenon-access stratum (e.g., control plane) functions such as mobility,authentication, and bearer management for UEs 115 served by basestations 105 associated with the EPC. User IP packets may be transferredthrough the S-GW, which itself may be connected to the P-GW. The P-GWmay provide IP address allocation as well as other functions. The P-GWmay be connected to the network operators IP services. The operators IPservices may include access to the Internet, Intranet(s), an IPMultimedia Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (e.g.,radio heads and access network controllers) or consolidated into asingle network device (e.g., a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 MHz to 300 GHz.Generally, the region from 300 MHz to 3 GHz is known as the ultra-highfrequency (UHF) region or decimeter band, since the wavelengths rangefrom approximately one decimeter to one meter in length. UHF waves maybe blocked or redirected by buildings and environmental features.However, the waves may penetrate structures sufficiently for a macrocell to provide service to UEs 115 located indoors. Transmission of UHFwaves may be associated with smaller antennas and shorter range (e.g.,less than 100 km) compared to transmission using the smaller frequenciesand longer waves of the high frequency (HF) or very high frequency (VHF)portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that can tolerate interference from otherusers.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some cases, wireless communications system 100 may utilize bothlicensed and unlicensed radio frequency spectrum bands. For example,wireless communications system 100 may employ License Assisted Access(LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technologyin an unlicensed band such as the 5 GHz ISM band. When operating inunlicensed radio frequency spectrum bands, wireless devices such as basestations 105 and UEs 115 may employ listen-before-talk (LBT) proceduresto ensure a frequency channel is clear before transmitting data. In somecases, operations in unlicensed bands may be based on a CA configurationin conjunction with CCs operating in a licensed band (e.g., LAA).Operations in unlicensed spectrum may include downlink transmissions,uplink transmissions, peer-to-peer transmissions, or a combination ofthese. Duplexing in unlicensed spectrum may be based on frequencydivision duplexing (FDD), time division duplexing (TDD), or acombination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving devices are equipped with one ormore antennas. MIMO communications may employ multipath signalpropagation to increase the spectral efficiency by transmitting orreceiving multiple signals via different spatial layers, which may bereferred to as spatial multiplexing. The multiple signals may, forexample, be transmitted by the transmitting device via differentantennas or different combinations of antennas. Likewise, the multiplesignals may be received by the receiving device via different antennasor different combinations of antennas. Each of the multiple signals maybe referred to as a separate spatial stream, and may carry bitsassociated with the same data stream (e.g., the same codeword) ordifferent data streams. Different spatial layers may be associated withdifferent antenna ports used for channel measurement and reporting. MIMOtechniques include single-user MIMO (SU-MIMO) where multiple spatiallayers are transmitted to the same receiving device, and multiple-userMIMO (MU-MIMO) where multiple spatial layers are transmitted to multipledevices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In one example, a base station 105 may use multiple antennas or antennaarrays to conduct beamforming operations for directional communicationswith a UE 115. For instance, some signals (e.g., synchronizationsignals, reference signals, beam selection signals, or other controlsignals) may be transmitted by a base station 105 multiple times indifferent directions, which may include a signal being transmittedaccording to different beamforming weight sets associated with differentdirections of transmission. Transmissions in different beam directionsmay be used to identify (e.g., by the base station 105 or a receivingdevice, such as a UE 115) a beam direction for subsequent transmissionand/or reception by the base station 105. Some signals, such as datasignals associated with a particular receiving device, may betransmitted by a base station 105 in a single beam direction (e.g., adirection associated with the receiving device, such as a UE 115). Insome examples, the beam direction associated with transmissions along asingle beam direction may be determined based at least in in part on asignal that was transmitted in different beam directions. For example, aUE 115 may receive one or more of the signals transmitted by the basestation 105 in different directions, and the UE 115 may report to thebase station 105 an indication of the signal it received with a highestsignal quality, or an otherwise acceptable signal quality. Althoughthese techniques are described with reference to signals transmitted inone or more directions by a base station 105, a UE 115 may employsimilar techniques for transmitting signals multiple times in differentdirections (e.g., for identifying a beam direction for subsequenttransmission or reception by the UE 115), or transmitting a signal in asingle direction (e.g., for transmitting data to a receiving device).

A receiving device (e.g., a UE 115, which may be an example of a mmWreceiving device) may try multiple receive beams when receiving varioussignals from the base station 105, such as synchronization signals,reference signals, beam selection signals, or other control signals. Forexample, a receiving device may try multiple receive directions byreceiving via different antenna subarrays, by processing receivedsignals according to different antenna subarrays, by receiving accordingto different receive beamforming weight sets applied to signals receivedat a plurality of antenna elements of an antenna array, or by processingreceived signals according to different receive beamforming weight setsapplied to signals received at a plurality of antenna elements of anantenna array, any of which may be referred to as “listening” accordingto different receive beams or receive directions. In some examples areceiving device may use a single receive beam to receive along a singlebeam direction (e.g., when receiving a data signal). The single receivebeam may be aligned in a beam direction determined based at least inpart on listening according to different receive beam directions (e.g.,a beam direction determined to have a highest signal strength, highestsignal-to-noise ratio, or otherwise acceptable signal quality based atleast in part on listening according to multiple beam directions).

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-basednetwork that operate according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may insome cases perform packet segmentation and reassembly to communicateover logical channels. A Medium Access Control (MAC) layer may performpriority handling and multiplexing of logical channels into transportchannels. The MAC layer may also use hybrid automatic repeat request(HARQ) to provide retransmission at the MAC layer to improve linkefficiency. In the control plane, the Radio Resource Control (RRC)protocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 115 and a base station 105 or corenetwork 130 supporting radio bearers for user plane data. At thePhysical (PHY) layer, transport channels may be mapped to physicalchannels.

In some cases, UEs 115 and base stations 105 may support retransmissionsof data to increase the likelihood that data is received successfully.HARQ feedback is one technique of increasing the likelihood that data isreceived correctly over a communication link 125. HARQ may include acombination of error detection (e.g., using a cyclic redundancy check(CRC)), forward error correction (FEC), and retransmission (e.g.,automatic repeat request (ARQ)). HARQ may improve throughput at the MAClayer in poor radio conditions (e.g., signal-to-noise conditions). Insome cases, a wireless device may support same-slot HARQ feedback, wherethe device may provide HARQ feedback in a specific slot for datareceived in a previous symbol in the slot. In other cases, the devicemay provide HARQ feedback in a subsequent slot, or according to someother time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period ofT_(s)=1/30,720,000 seconds. Time intervals of a communications resourcemay be organized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (e.g., depending on the length of the cyclic prefix prepended toeach symbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases a subframe may be thesmallest scheduling unit of the wireless communications system 100, andmay be referred to as a transmission time interval (TTI). In othercases, a smallest scheduling unit of the wireless communications system100 may be shorter than a subframe or may be dynamically selected (e.g.,in bursts of shortened TTIs (sTTIs) or in selected component carriersusing sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resourceshaving a defined physical layer structure for supporting communicationsover a communication link 125. For example, a carrier of a communicationlink 125 may include a portion of a radio frequency spectrum band thatis operated according to physical layer channels for a given radioaccess technology. Each physical layer channel may carry user data,control information, or other signaling. A carrier may be associatedwith a pre-defined frequency channel (e.g., an E-UTRA absolute radiofrequency channel number (EARFCN)), and may be positioned according to achannel raster for discovery by UEs 115. Carriers may be downlink oruplink (e.g., in an FDD mode), or be configured to carry downlink anduplink communications (e.g., in a TDD mode). In some examples, signalwaveforms transmitted over a carrier may be made up of multiplesub-carriers (e.g., using multi-carrier modulation (MCM) techniques suchas OFDM or DFT-s-OFDM).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR,etc.). For example, communications over a carrier may be organizedaccording to TTIs or slots, each of which may include user data as wellas control information or signaling to support decoding the user data. Acarrier may also include dedicated acquisition signaling (e.g.,synchronization signals or system information, etc.) and controlsignaling that coordinates operation for the carrier. In some examples(e.g., in a carrier aggregation configuration), a carrier may also haveacquisition signaling or control signaling that coordinates operationsfor other carriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (e.g., between acommon control region or common search space and one or more UE-specificcontrol regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or RBs) within a carrier (e.g., “in-band” deployment of anarrowband protocol type).

In a system employing MCM techniques, a resource element may include onesymbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth, or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 and/or UEs that can support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth.

Wireless communications system 100 may support communication with a UE115 on multiple cells or carriers, a feature which may be referred to ascarrier aggregation (CA) or multi-carrier operation. A UE 115 may beconfigured with multiple downlink CCs and one or more uplink CCsaccording to a carrier aggregation configuration. Carrier aggregationmay be used with both FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhancedcomponent carriers (eCCs). An eCC may be characterized by one or morefeatures including wider carrier or frequency channel bandwidth, shortersymbol duration, shorter TTI duration, or modified control channelconfiguration. In some cases, an eCC may be associated with a carrieraggregation configuration or a dual connectivity configuration (e.g.,when multiple serving cells have a suboptimal or non-ideal backhaullink). An eCC may also be configured for use in unlicensed spectrum orshared spectrum (e.g., where more than one operator is allowed to usethe spectrum). An eCC characterized by wide carrier bandwidth mayinclude one or more segments that may be utilized by UEs 115 that arenot capable of monitoring the whole carrier bandwidth or are otherwiseconfigured to use a limited carrier bandwidth (e.g., to conserve power).

In some cases, an eCC may utilize a different symbol duration than otherCCs, which may include use of a reduced symbol duration as compared withsymbol durations of the other CCs. A shorter symbol duration may beassociated with increased spacing between adjacent subcarriers. Adevice, such as a UE 115 or base station 105, utilizing eCCs maytransmit wideband signals (e.g., according to frequency channel orcarrier bandwidths of 20, 40, 60, 80 MHz, etc.) at reduced symboldurations (e.g., 16.67 microseconds). A TTI in eCC may include one ormultiple symbol periods. In some cases, the TTI duration (that is, thenumber of symbol periods in a TTI) may be variable.

Wireless communications systems such as an NR system may utilize anycombination of licensed, shared, and unlicensed spectrum bands, amongothers. The flexibility of eCC symbol duration and subcarrier spacingmay allow for the use of eCC across multiple spectrums. In someexamples, NR shared spectrum may increase spectrum utilization andspectral efficiency, specifically through dynamic vertical (e.g., acrossfrequency) and horizontal (e.g., across time) sharing of resources.

One or more of the base stations 105 may include a communicationsmanager 101, which may transmit a reference signal on one or more anchorchannels at the start of a frame (e.g., an m-frame). The communicationsmanager 101 may also perform a first random or pseudorandom frequencyhopping procedure to identify a plurality of downlink carriers fordownlink segments of the frame. The communications manager 101 maytransmit downlink communications to one or more UEs 115 during downlinksegments of the frame using the identified plurality of downlinkcarriers.

The communications manager 101 may identify an anticipated collisionbetween two or more UEs 115 during an uplink segment of the frame. Thecommunications manager 101 may identify the anticipated collision for anupcoming uplink segment based at least in part on the selectionprocedure (e.g., algorithm) used by the UEs 115 for the upcoming uplinksegment. The communications manager 101 may transmit time divisionmultiplexing (TDM) information to the UEs 115 based at least in part onthe identified anticipated collision. In some examples, thecommunications manager 101 may transmit the TDM information to the UEs115 in the downlink communications.

UEs 115 may include a communications manager 102, which may perform afirst random or pseudorandom frequency hopping procedure to identify afirst plurality of downlink carriers for downlink segments of a firstframe. The communications manager 102 may also perform a second randomor pseudorandom frequency hopping procedure within the first pluralityof downlink carriers to select an uplink channel for an uplink segmentof the first frame.

In some examples, the second random or pseudorandom frequency hoppingprocedure may include randomly or pseudo-randomly selecting an uplinkchannel from the first plurality of downlink carriers. In some examples,the second random or pseudorandom frequency hopping procedure mayinclude randomly or pseudo-randomly selecting a permutation of the firstplurality of downlink carriers, and then selecting the uplink channelbased at least in part on the selected permutation. In some examples,the second random or pseudorandom frequency hopping procedure mayinclude randomly or pseudo-randomly selecting a primary channel.

The communications manager 102 may transmit an uplink communication onthe selected uplink channel during the uplink segment of the firstframe. In some examples, the first frame may include two or more uplinkssegments. The communications manager 102 may perform a random orpseudorandom frequency hopping procedure for each uplink segment. Forexample, the communications manager 102 may perform a third random orpseudorandom frequency hopping procedure within the first plurality ofdownlink carriers to select a second uplink channel for a second uplinksegment of the first frame. The third random or pseudorandom frequencyhopping procedure may use the same selection procedure (e.g., algorithm)as the second random or pseudorandom frequency hopping procedure.

In some examples, the communications manager 102 may receive TDMinformation for an uplink segment (e.g., in a downlink communicationfrom a base station 105). In such examples, the communications manager102 may transmit the uplink communication during the uplink segmentbased at least in part on the TDM information. In some cases, forcinguplink transmission to be TDM'ed on a single carrier may hit the uplinkcapacity.

FIG. 2 illustrates an example of a wireless communications system 200that supports nested frequency hopping for data transmission inaccordance with various aspects of the present disclosure. In someexamples, the wireless communications system 200 may implement aspectsof wireless communications system 100.

The wireless communications system 200 may include a serving basestation 205, which may be an example of aspects of base station 105 asdescribed with reference to FIG. 1 . The wireless communications system200 may also include a plurality of served UEs 210 including a first UE210-a, a second UE 215-a, and a third UE 220-a. The served UEs 210 maybe examples of aspects of UEs 115 as described with reference to FIG. 1.

Each UE 210 may receive downlink communications from the base station205 and may transmit uplink communications to base station 205. The UE210 may communicate with the base station 205 according to a framestructure including at least one downlink segment and at least oneuplink segment. The frame structure may be, for example, an m-framestructure.

At the start of each frame, the base station 205 may transmit adiscovery reference signal (DRS) on at least one anchor channel. Forexample, the base station 205 may transmit a DRS on at least threeanchor channels or carriers simultaneously. Each anchor channel maycorrespond to one resource block. The anchor channels may be resourceblocks that are designated for transmitting a DRS and that are usedexclusively or primarily for the transmission of the DRS and othercontrol signals. The resource blocks used for the anchor channels may beknown to the base station 205 and the plurality of UEs 210 before theDRS is transmitted. For example, the base station 205 may identify theanchor channels when one of the UEs 210 joins the cell. In someexamples, the DRS may have a standard duration such as 10 millisecondsor 20 milliseconds.

The base station 205 may then transmit downlink communications to theplurality of UEs 210 during the downlink segment of the first frame. Insome examples, the base station 205 and the UEs 210 may be capable ofcommunicating on a number of different channels (e.g., resource bands).The base station 205 may select three of the available n channels, e.g.,to satisfy a minimum bandwidth constraint such as the FCC minimumbandwidth restraint for a shared spectrum. In some examples, eachchannel may serve a UE, e.g., the three channels may serve the three UEs210. In some other examples, the three channels may serve three sets ofUEs. The base station 205 and UEs 210 may use frequency hoppingprocedures to select the channels on which they will communicate.

The base station 205 and the UEs 210 may each perform a first random orpseudorandom frequency hopping procedure (e.g., a first stage or levelof random hopping) to select a first plurality of downlink carriers forthe first frame. In some examples, the first plurality of downlinkcarriers may include a plurality of contiguous channels. The basestation 205 may communicate with each of the UEs 210 using one of thefirst plurality of downlink carriers. In some cases, a UE 210 mayperform the first stage of random hopping for a group of M frequencies,where M is an integer, according to a hopping pattern determined by thebase station 205, and the UE 210 may receive downlink control and/ordata on a designated carrier.

Each UE 210 may then perform second random or pseudorandom frequencyhopping procedure within the first plurality of downlink carriers toselect an uplink carrier for the uplink segment of the first frame. EachUE 210 may randomly or pseudo-randomly select an uplink carrier based atleast in part on a random or pseudorandom number generator, or a randomor pseudorandom pattern. For example, the random generator for eachcarrier may pick one of the M hopping frequencies from the first levelof hopping. In some examples, the selection of an uplink carrier at oneof the UEs 210 (e.g., first UE 210-a) may be independent of theselection of the uplink carrier at the other UEs 210 in the wirelesscommunications system 200 (e.g., second UE 210-b and third UE 210-c). Insome examples, UEs 210 on a same downlink carriers may pick a samehopping pattern. In some other examples, each UE 210 may use a commonalgorithm to select the uplink carrier (e.g., to select a common primarycarrier or a common permutation).

In some examples, each UE 210 may randomly or pseudo-randomly select theuplink channel from the first plurality of downlink carriers. Forexample, the first plurality of downlink carriers may include threechannels A, B, and C. Each UE 210 may randomly or pseudo-randomly selectone of the three channels. For example, the first UE 210-a may selectchannel B, the second UE 210-b may select channel C, and the third UE210-c may select channel A. The UEs 210 may then transmit an uplinkcommunication on the selected uplink channel during the uplink segmentof the first frame. For example, the first UE 210-a may transmit anuplink communication on channel B, the second UE 210-b may transmit anuplink communication on channel C, and the third UE 210-c may transmitan uplink communication on channel A.

In some examples, each UE 210 may randomly or pseudo-randomly select apermutation of the first plurality of downlink carriers, and then selectthe uplink channel based at least in part on the selected permutation.For example, the first plurality of downlink carriers may include threechannels A, B, and C. There are six potential permutations of thesechannels. Each UE 210 may randomly or pseudo-randomly select one of thepermutations using a common algorithm, such that each UE 210 selects thesame permutation. For example, each UE 210 may select the permutation{B, C, A}. Each UE 210 may then select an uplink channel based on theselected permutation. For example, the first UE 210-a may select channelB, the second UE 210-b may select channel C, and the third UE 210-c mayselect channel A. The UEs 210 may then transmit an uplink communicationon the selected uplink channel during the uplink segment of the firstframe. For example, the first UE 210-a may transmit an uplinkcommunication on channel B, the second UE 210-b may transmit an uplinkcommunication on channel C, and the third UE 210-c may transmit anuplink communication on channel A.

In some examples, the UE 210 may randomly or pseudo-randomly select aprimary channel as the first uplink channel. For example, the firstplurality of downlink carriers may include three channels A, B, and C.Each UE 210 may randomly or pseudo-randomly select a primary channelusing a common algorithm, such that each UE 210 selects the same primarychannel. For example, each UE 210 may select channel B as the primarychannel. The UEs 210 may then transmit an uplink communication on theselected primary channel during the uplink segment of the first frame.

In some examples, one or more of the UEs 210 may select a same uplinkchannel. The base station 205 may identify an anticipated collisionbased at least in part on the selection procedure (e.g., the algorithm)used by the UEs 210 to select the uplink channel. The base station 205may provide TDM information to the UEs 210 in the downlinkcommunication. One or more of the UEs 210 may transmit their uplinkcommunications on the same uplink channel during the uplink segment ofthe first frame based at least in part on the TDM information. In someexamples, two UEs 210 from different carriers may hop on a same hoppingfrequencies and a scheduler at the base station 205 may carefully TDMuplink transmission(s) on the same hopping frequencies.

In some examples, the first frame may include one or more additionaldownlink and uplink segments. The base station 205 may transmitadditional downlink communications during the additional downlinksegments using the assignments determined in the first frequency hoppingprocedure. The UEs 210 may perform additional frequency hoppingprocedures for each additional uplink segment to select an uplinkchannel from the first plurality of downlink carriers. For example, fora second uplink segment in the first frame, the first UE 210-a mayperform a third frequency hopping procedure, which may use the sameselection procedure (e.g., algorithm) used above for the secondfrequency hopping procedure. The first UE 210-a may identify channel Aas the uplink channel for the second uplink segment based on the thirdfrequency hopping procedure.

At the start of the second frame, the base station 205 may transmit asecond reference signal. The base station 205 and the UEs 210 may thenperform a third random or pseudorandom frequency hopping procedure toidentify a second plurality of downlink carriers for the second frame.The third random or pseudorandom frequency hopping procedure may use thesame selection procedure (e.g., algorithm) as the first frequencyhopping procedure.

The UEs 210 may perform a fourth random or pseudorandom frequencyhopping procedure within the second plurality of downlink carriers toselect an uplink carrier for an uplink segment of the second frame. Thefourth frequency hopping procedure may use the same selection procedure(e.g., algorithm) used above for the second frequency hopping procedure.The UEs 210 may then transmit uplink communications on the selecteduplink carrier during the uplink segment of the second frame.

FIG. 3 illustrates an example of a communication sequence 300 in awireless communication system that supports nested frequency hopping fordata transmission in accordance with various aspects of the presentdisclosure. In some examples, the wireless communication system mayimplement aspects of wireless communications system 100.

The communication sequence 300 may show downlink communications from abase station to a plurality of UEs, and uplink communications from theplurality of UEs to the base station. The base station and the UEs maybe examples of aspects of base station 105 and UEs 115 as described withreference to FIG. 1 . The communication sequence 300 includes a firstframe 305 and a second frame 310. Each frame may be, for example, anm-frame. In some examples, each frame may have a standard duration suchas 160 milliseconds or 320 milliseconds. The first frame 305 includes afirst time period 380 corresponding to a downlink segment and a secondtime period 385 corresponding to an uplink segment. The second timeframe 310 includes a third time period 390 corresponding to a downlinksegment and a fourth time period 395 corresponding to an uplink segment.

At the start of the first frame 305, the base station 105 may transmit adiscovery reference signal (DRS) 315 on at least one anchor channel.Each anchor channel may correspond to one resource block. The anchorchannels may be resource blocks that are designated for transmitting aDRS and that are used exclusively or primarily for the transmission ofthe DRS and other control signals. The resource blocks used for theanchor channels may be known to the base station 105 and the pluralityof UEs 115 before the DRS is transmitted. For example, the base station105 may identify the anchor channels when a UE 115 joins the cell. Insome examples, the DRS may have a standard duration such as 10milliseconds or 20 milliseconds.

The base station 105 and the UEs 115 may perform a first random orpseudorandom frequency hopping procedure to select and/or identify afirst plurality of downlink carriers for downlink segments of the firstframe 305. In some examples, the base station 105 and the UEs 115 mayselect and/or identify the first plurality of downlink carriers based atleast in part on a pseudorandom sequence known to both the base station105 and the UEs 115.

In some examples, the first plurality of downlink carriers may include aset of three or more contiguous data channels (e.g., three or morecontiguous channels starting with a first channel corresponding tohopping frequency 1). The first plurality of downlink carriers for thefirst frame 305 may be, with respect to FIG. 3 , a first channelcorresponding to hopping frequency 1, a second channel corresponding tohopping frequency 2, and a third channel corresponding to hoppingfrequency 3. Each downlink carrier may correspond to a resource block.

The base station 105 may transmit downlink data on one or more of thefirst plurality of downlink carriers during downlink segments of thefirst frame 305. For example, during the first time period 380, the basestation 105 may transmit downlink data 320 for a first UE (UE0) on afirst channel corresponding to hopping frequency 1, downlink data 325for a second UE (UE1) on a second channel corresponding to hoppingfrequency 2, and downlink data 330 for a third UE (UE2) on a thirdchannel corresponding to hopping frequency 3. The base station 105 mayuse the same downlink carrier assignments for any additional downlinkcommunications during the first time frame 305.

Each UE 115 may perform a second random or pseudorandom frequencyhopping procedure within the first plurality of downlink carriers toselect one of the first plurality of downlink channels as an uplinkchannel for the second time period 385. For example, each UE 115 mayrandomly or pseudo-randomly select one of the first plurality ofdownlink carriers as the uplink channel. In some examples, the UE 115may randomly or pseudo-randomly select one of the first plurality ofdownlink carriers based at least in part on a random or pseudorandomnumber generator. In some examples, the UE 115 may select one of thefirst plurality of downlink carriers based at least in part on a randomor pseudorandom pattern. The selection of the uplink channel at one UE(e.g., first UE (UE0)) may be independent of the selection of the uplinkchannel at other UEs in a cell (e.g., second UE (UE1) and third UE(UE2)).

For example, with reference to FIG. 3 , a first UE (UE0) may randomly orpseudo-randomly select a second channel corresponding to hoppingfrequency 2 as the uplink channel. A second UE (UE1) may select a firstchannel corresponding to hopping frequency 1 as the uplink channel. Athird UE (UE2) may select a third channel corresponding to hoppingfrequency 3 as the uplink channel. In some examples, a UE 115 mayrandomly or pseudo-randomly select an uplink channel that is differentthan the channel on which it received downlink data (e.g., UE0 and UE1).In some examples, a UE 115 may randomly or pseudo-randomly select anuplink channel that is the same as the channel on which it receiveddownlink data (e.g., UE2).

The UEs 115 may transmit uplink communications on the selected uplinkchannels during the second time period 385. For example, the first UE(UE0) may transmit an uplink communication 335 on the second channel,the second UE (UE1) may transmit an uplink communication 340 on thefirst channel, and the third UE (UE2) may transmit an uplinkcommunication 345 on the third channel.

At the start of the second frame 310, the base station 105 may transmita second DRS 350 on the at least one anchor channel, as described abovewith respect to DRS 315.

The base station 105 and the UEs 115 may perform a third random orpseudorandom frequency hopping procedure to select and/or identify asecond plurality of downlink carriers for downlink segments of thesecond frame 310. The UEs 115 may perform the third random orpseudorandom frequency hopping procedure as described above with respectto the first random or pseudorandom frequency hopping procedure. In someexamples, the base station 105 and the UEs 115 may select and/oridentify the second plurality of downlink carriers based at least inpart on a pseudorandom sequence known to both the base station 105 andthe UEs 115. In some examples, the base station 105 and the UEs 115 mayselect and/or identify the second plurality of downlink carriers basedat least in part on the first plurality of downlink carriers, e.g., thesecond plurality of downlink carriers may include a set of three or morecontiguous downlink carriers starting with the second data channel inthe first plurality of downlink carriers (e.g., the second channelcorresponding to hopping frequency 2). The second plurality of downlinkcarriers for the second frame 310 may be, with respect to FIG. 3 , asecond channel corresponding to hopping frequency 2, a third channelcorresponding to hopping frequency 3, and a fourth channel correspondingto hopping frequency 4. Each channel may correspond to a resource block.

The base station 105 may transmit downlink data on one or more of thesecond plurality of downlink carriers. For example, during the thirdtime period 390, the base station 105 may transmit downlink data 355 fora first UE (UE0) on a second channel corresponding to hopping frequency2, downlink data 360 for a second UE (UE1) on a third channelcorresponding to hopping frequency 3, and downlink data 365 for a thirdUE (UE2) on a fourth channel corresponding to hopping frequency 4. Thebase station 105 may use the same downlink carrier assignments for anyadditional downlink communications during the second time frame 310.

Each UE 115 may perform a fourth random or pseudorandom frequencyhopping procedure within the second plurality of downlink carriers toselect one of the second plurality of downlink channels as a seconduplink channel for the fourth time period 395. The UE 115 may performthe fourth random or pseudorandom frequency hopping procedure asdescribed above with respect to the second random or pseudorandomfrequency hopping procedure.

In some examples, two or more UEs 115 may select the same downlinkcarrier as an uplink channel for the fourth time period 395. Forexample, in the fourth time period 395, the first UE (UE0) and thesecond UE (UE1) may select the fourth channel as the uplink channel,while the third UE (UE2) may select the second channel as the uplinkchannel.

The base station 105 may identify an anticipated collision between thefirst UE (UE0) and the second UE (UE1). For example, the base station105 may identify an anticipated collision based at least in part on aselection procedure (e.g., a pseudorandom pattern) used by each UE. Thebase station 105 may provide time division multiplexing information tothe first UE (UE0) and the second UE (UE1). In some examples, the basestation 105 may transmit the time division multiplexing information inthe downlink communications 355, 360, and 365 of third time period 390(e.g., in a final segment of the downlink communications).

The UEs 115 may transmit uplink communications on the selected uplinkchannels during the fourth time period 395. For example, the third UE(UE2) may transmit an uplink communication 370 on the second channel.The first UE (UE0) and second UE (UE1) may transmit uplinkcommunications 375 on the fourth channel based at least in part on thetime division multiplexing information.

FIG. 4 illustrates an example of a communication sequence 400 in awireless communication system that supports nested frequency hopping fordata transmission in accordance with various aspects of the presentdisclosure. In some examples, the wireless communication system mayimplement aspects of wireless communications system 100.

The communication sequence 400 may show downlink communications from abase station to a plurality of UEs, and uplink communications from theplurality of UEs to the base station. The base station and the UEs maybe examples of aspects of base station 105 and UEs 115 as described withreference to FIG. 1 . The communication sequence 400 includes a firstframe 405 and a second frame 410, which may be examples of aspects offirst frame 305 and second frame 310 as described with reference to FIG.3 . The first frame 405 includes a first time period 485 correspondingto a downlink segment and a second time period 490 corresponding to anuplink segment. The second frame 410 includes a third time period 495corresponding to a downlink segment and a fourth time period 499corresponding to an uplink segment.

At the start of the first frame 405, the base station 105 may transmit afirst DRS 415 on at least one anchor channel, as described above withreference to FIG. 3 .

The base station 105 and the plurality of UEs 115 may perform a firstrandom or pseudorandom frequency hopping procedure to select and/oridentify a first plurality of downlink carriers for the first frame 405.In some examples, the base station 105 and the UEs 115 may select and/oridentify the first plurality of downlink carriers based at least in parton a pseudorandom sequence known to both the base station 105 and theUEs 115. The first plurality of downlink carriers may be, with respectto FIG. 4 , a first channel corresponding to hopping frequency 1, asecond channel corresponding to hopping frequency 2, and a third channelcorresponding to hopping frequency 3.

The base station 105 may transmit downlink data on one or more of thefirst plurality of data channels during first time period 485. Forexample, during a first time period corresponding to the downlinksegment of the first frame 405, the base station 105 may transmitdownlink data 420 for a first UE (UE0) on a first channel correspondingto hopping frequency 1, downlink data 425 for a second UE (UE1) on asecond channel corresponding to hopping frequency 2, and downlink data430 for a third UE (UE2) on a third channel corresponding to hoppingfrequency 3. The base station 105 may use the same downlink carrierassignments for any additional downlink communications during the firstframe 405.

Each UE 115 may perform a second random or pseudorandom frequencyhopping procedure within the first plurality of downlink carriers toselect one of the first plurality of downlink channels as an uplinkchannel for a second time period 490. For example, a UE 115 may randomlyor pseudo-randomly select a permutation of the first plurality ofdownlink carriers. For example, for three UEs 115 transmitting overthree downlink carriers (as shown in FIG. 4 ), there may be six possiblepermutations: {0, 1, 2}, {0, 2, 1}, {1, 0, 2}, {1, 2, 0}, {2, 0, 1}, and{2, 1, 0}. The UE 115 may randomly or pseudo-randomly select one of thesix permutations. Each UE 115 may select the permutation using the sameselection procedure, such that each UE 115 selects the same permutation.For example, each UE 115 may randomly or pseudo-randomly select thepermutation {1, 0, 2}. The UE 115 may select the permutation based atleast in part on a random or pseudorandom number generator, a random orpseudorandom pattern, or the like.

The UE 115 may select the uplink channel based at least in part on theselected permutation. For example, based on the permutation {1, 0, 2},the second UE (UE1) may select a first channel in a contiguous set ofchannels (corresponding to hopping frequency 1), the first UE (UE0) mayselect a second channel in the contiguous set of channels (correspondingto hopping frequency 2), and the third UE (UE2) may select a thirdchannel in the contiguous set of channels (corresponding to hoppingfrequency 3).

The UEs 115 may transmit uplink communications on the selected uplinkchannels during the second time period 490. For example, the first UE(UE0) may transmit an uplink communication 435 on the second channel,the second UE (UE1) may transmit an uplink communication 440 on thefirst channel, and the third UE (UE2) may transmit an uplinkcommunication 445 on the third channel.

At the start of the second frame 410, the base station 105 may transmita second DRS 450 on the at least one anchor channel, as described abovewith respect to DRS 415.

The base station 105 and the UEs 115 may perform a third random orpseudorandom frequency hopping procedure to select and/or identify asecond plurality of downlink carriers for downlink segments of thesecond frame 410. The UEs 115 may perform the third random orpseudorandom frequency hopping procedure as described above with respectto the first random or pseudorandom frequency hopping procedure. In someexamples, the base station 105 and the UEs 115 may select and/oridentify the second plurality of downlink carriers based at least inpart on a pseudorandom sequence known to both the base station 105 andthe UEs 115. In some examples, the base station 105 and the UEs 115 mayselect and/or identify the second plurality of downlink carriers basedat least in part on the first plurality of downlink carriers, e.g., thesecond plurality of downlink carriers may include a set of three or morecontiguous downlink carriers starting with the second data channel inthe first plurality of downlink carriers (e.g., the second channelcorresponding to hopping frequency 2). The second plurality of downlinkcarriers for the second frame 410 may be, with respect to FIG. 4 , asecond channel corresponding to hopping frequency 2, a third channelcorresponding to hopping frequency 3, and a fourth channel correspondingto hopping frequency 4. Each channel may correspond to a resource block.

The base station 105 may transmit downlink data on one or more of thesecond plurality of downlink carriers. For example, during a third timeperiod 495, the base station 105 may transmit downlink data 455 for afirst UE (UE0) on a second channel corresponding to hopping frequency 2,downlink data 460 for a second UE (UE1) on a third channel correspondingto hopping frequency 3, and downlink data 465 for a third UE (UE2) on afourth channel corresponding to hopping frequency 4. The base station105 may use the same downlink carrier assignments for any additionaldownlink communications during the second frame 410.

Each UE 115 may perform a fourth random or pseudorandom frequencyhopping procedure within the second plurality of downlink carriers toselect one of the second plurality of downlink channels as a seconduplink channel for a fourth time period 499. The UE 115 may perform thefourth random or pseudorandom frequency hopping procedure as describedabove with respect to the second random or pseudorandom frequencyhopping procedure. In contrast to the selection scheme described withreference to FIG. 3 , the random or pseudorandom selection of apermutation of the downlink carriers may avoid collisions, and as suchno time division multiplexing information may be transmitted.

The UEs 115 may select a second permutation of the second plurality ofdownlink, e.g., {2, 0, 1}. The UEs 115 may select a second uplinkchannel based at least in part on the second permutation. For example,based on the permutation {2, 0, 1}, the third UE (UE2) may select afirst channel in a contiguous set of channels (corresponding to hoppingfrequency 2), the first UE (UE0) may select a second channel in thecontiguous set of channels (corresponding to hopping frequency 3), andthe second UE (UE1) may select a third channel in the contiguous set ofchannels (corresponding to hopping frequency 4). The UEs 115 maytransmit uplink communications on the selected uplink channels duringthe fourth time period 499. For example, the first UE (UE0) may transmitan uplink communication 470 on the channel corresponding to hoppingfrequency 3, the second UE (UE1) may transmit an uplink communication475 on the channel corresponding to hopping frequency 4, and the thirdUE (UE2) may transmit an uplink communication 480 on the channelcorresponding to hopping frequency 2.

FIG. 5 illustrates an example of a communication sequence 500 in awireless communication system that supports nested frequency hopping fordata transmission in accordance with various aspects of the presentdisclosure. In some examples, the wireless communication system mayimplement aspects of wireless communications system 100.

The communication sequence 500 may show downlink communications from abase station to a plurality of UEs, and uplink communications from theplurality of UEs to the base station. The base station and the UEs maybe examples of aspects of base station 105 and UEs 115 as described withreference to FIG. 1 . The communication sequence 500 includes a firstframe 505 and a second frame 510, which may be examples of aspects offirst frame 305 and second frame 310 as described with reference to FIG.3 . The first frame 505 includes a first time period 565 correspondingto a downlink segment and a second time period 570 corresponding to anuplink segment. The second frame 510 includes a third time period 575corresponding to a downlink segment and a fourth time period 580corresponding to an uplink segment.

At the start of the first frame 505, the base station 105 may transmit afirst DRS 515 on at least one anchor channel, as described above withreference to FIG. 3 . For example, the base station 205 may transmit aDRS on at least three anchor channels or carriers simultaneously.

The base station 105 and the plurality of UEs 115 may perform a firstrandom or pseudorandom frequency hopping procedure to select and/oridentify a first plurality of downlink carriers for the first frame 505.In some examples, the base station 105 and the UEs 115 may select and/oridentify the first plurality of downlink carriers based at least in parton a pseudorandom sequence known to both the base station 105 and theUEs 115. The first plurality of downlink carriers may be, with respectto FIG. 5 , a first channel corresponding to hopping frequency 1, asecond channel corresponding to hopping frequency 2, and a third channelcorresponding to hopping frequency 3.

The base station 105 may transmit downlink data on one or more of thefirst plurality of data channels during downlink segments of the firstframe 505. For example, during the first time period 565, the basestation 105 may transmit downlink data 520 for a first UE (UE0) on afirst channel corresponding to hopping frequency 1, downlink data 525for a second UE (UE1) on a second channel corresponding to hoppingfrequency 2, and downlink data 530 for a third UE (UE2) on a thirdchannel corresponding to hopping frequency 3. The base station 105 mayuse the same downlink carrier assignments for any additional downlinkcommunications during the first frame 505.

Each UE 115 may perform a second random or pseudorandom frequencyhopping procedure within the first plurality of downlink carriers toselect one of the first plurality of downlink channels as an uplinkchannel for the second time period 570. For example, a UE 115 mayrandomly or pseudo-randomly select a primary channel from the firstplurality of downlink carriers. In some examples, the UE 115 mayrandomly or pseudo-randomly select one of the first plurality ofdownlink carriers based at least in part on a random or pseudorandomnumber generator. In some examples, the UE 115 may select one of thefirst plurality of downlink carriers based at least in part on a randomor pseudorandom pattern. The primary channel is a channel which will beused for uplink communications by all UEs 115 in the cell during thetime period (e.g., during second time period 570). In some examples,each UE 115 may independently identify and/or select the primarychannel. In some other examples, one UE 115 may identify and/or selectthe primary channel and communicate an indication of the primary channelto the other UEs 115 in the cell.

For example, each UE 115 may randomly or pseudo-randomly select a secondchannel corresponding to hopping frequency 2 as the uplink channel. TheUEs 115 may transmit uplink communications 535 on the primary channelduring the second time period 570. The UEs 115 may transmit the uplinkcommunications based at least in part on time division multiplexinginformation. In some examples, the base station 105 may transmit timedivision multiplexing information to the UEs 115, e.g., in the downlinkdata 520, 525, and 530 during the first time period 565 (e.g., in afinal segment of the downlink communications).

At the start of the second frame 510, the base station 105 may transmita second DRS 540 on the at least one anchor channel, as described abovewith respect to DRS 515.

The base station 105 and the UEs 115 may perform a third random orpseudorandom frequency hopping procedure to select and/or identify asecond plurality of downlink carriers for downlink segments of thesecond frame 510. The UEs 115 may perform the third random orpseudorandom frequency hopping procedure as described above with respectto the first random or pseudorandom frequency hopping procedure. In someexamples, the base station 105 and the UEs 115 may select and/oridentify the second plurality of downlink carriers based at least inpart on a pseudorandom sequence known to both the base station 105 andthe UEs 115. In some examples, the base station 105 and the UEs 115 mayselect and/or identify the second plurality of downlink carriers basedat least in part on the first plurality of downlink carriers, e.g., thesecond plurality of downlink carriers may include a set of three or morecontiguous downlink carriers starting with the second data channel inthe first plurality of downlink carriers (e.g., the second channelcorresponding to hopping frequency 2). The second plurality of downlinkcarriers for the second frame 510 may be, with respect to FIG. 5 , asecond channel corresponding to hopping frequency 2, a third channelcorresponding to hopping frequency 3, and a fourth channel correspondingto hopping frequency 4. Each channel may correspond to a resource block.

The base station 105 may transmit downlink data on one or more of thesecond plurality of downlink carriers. For example, during the thirdtime period 575, the base station 105 may transmit downlink data 545 fora first UE (UE0) on a second channel corresponding to hopping frequency2, downlink data 550 for a second UE (UE1) on a third channelcorresponding to hopping frequency 3, and downlink data 555 for a thirdUE (UE2) on a fourth channel corresponding to hopping frequency 4. Thebase station 105 may use the same downlink carrier assignments for anyadditional downlink communications during the second frame 510.

Each UE 115 may perform a fourth random or pseudorandom frequencyhopping procedure within the second plurality of downlink carriers toselect one of the second plurality of downlink channels as a seconduplink channel for the fourth time period 580. The UE 115 may performthe fourth random or pseudorandom frequency hopping procedure asdescribed above with respect to the second random or pseudorandomfrequency hopping procedure.

For example, each UE 115 may randomly or pseudo-randomly select a thirdchannel corresponding to hopping frequency 3 as the uplink channel. TheUEs 115 may transmit uplink communications 560 on the primary channelduring the fourth time period 580. The UEs 115 may transmit the uplinkcommunications based at least in part on second time divisionmultiplexing information. In some examples, the base station 105 maytransmit second time division multiplexing information to the UEs 115,e.g., in the downlink data 545, 550, and 555 during the third timeperiod 575 (e.g., in a final segment of the downlink communications).

FIG. 6 illustrates an example of a communication sequence 600 in awireless communication system that supports nested frequency hopping fordata transmission in accordance with various aspects of the presentdisclosure. In some examples, the wireless communication system mayimplement aspects of wireless communications system 100.

The communication sequence 600 may show downlink communications from abase station to a plurality of UEs, and uplink communications from theplurality of UEs to the base station. The base station and the UEs maybe examples of aspects of base station 105 and UEs 115 as described withreference to FIG. 1 . The communication sequence 600 includes a firstframe 605. Each frame may be, for example, an m-frame. In some examples,each frame may have a standard duration such as 160 milliseconds or 320milliseconds. The first frame 605 may include a first time period 675corresponding to a first downlink segment, a second time period 680corresponding to a first uplink segment, a third time period 685corresponding to a second downlink segment, and a fourth time period 690corresponding to a second uplink segment. In such cases, random hoppingfrequencies for multiple uplink segments of a UE 115 may be on differenthopping frequencies within the same m-frame, thereby alleviatingfrequency collision(s).

At the start of the first frame 605, the base station 105 may transmit afirst DRS 610 on at least one anchor channel, as described above withreference to FIG. 3 .

The base station 105 and the plurality of UEs 115 may perform a firstrandom or pseudorandom frequency hopping procedure to select and/oridentify a first plurality of downlink carriers for the first frame 605.In some examples, the base station 105 and the UEs 115 may select and/oridentify the first plurality of downlink carriers based at least in parton a pseudorandom sequence known to both the base station 105 and theUEs 115. The first plurality of downlink carriers may be, with respectto FIG. 6 , a first channel corresponding to hopping frequency 1, asecond channel corresponding to hopping frequency 2, and a third channelcorresponding to hopping frequency 3.

The base station 105 may transmit downlink data on one or more of thefirst plurality of data channels during the first time period 675. Forexample, during the first time period 675, the base station 105 maytransmit downlink data 615 for a first UE (UE0) on a first channelcorresponding to hopping frequency 1, downlink data 620 for a second UE(UE1) on a second channel corresponding to hopping frequency 2, anddownlink data 625 for a third UE (UE2) on a third channel correspondingto hopping frequency 3.

Each UE 115 may perform a second random or pseudorandom frequencyhopping procedure within the first plurality of downlink carriers toselect one of the first plurality of downlink channels as a first uplinkchannel for the second time period 680. In some examples, the UE 115 mayrandomly or pseudo-randomly select the uplink channel from the firstplurality of downlink carriers, as described above with respect to FIG.3 . In some examples, the UE 115 may randomly or pseudo-randomly selecta permutation of the first plurality of downlink carriers, and thenselect the first uplink channel based at least in part on the selectedpermutation, as described above with respect to FIG. 4 . In someexamples, the UE 115 may randomly or pseudo-randomly select a primarychannel as the first uplink channel, as described above with respect toFIG. 5 .

For example, with reference to FIG. 6 , a first UE (UE0) may randomly orpseudo-randomly select a second channel corresponding to hoppingfrequency 2 as the first uplink channel. A second UE (UE1) may select afirst channel corresponding to hopping frequency 1 as the first uplinkchannel. A third UE (UE2) may select a third channel corresponding tohopping frequency 3 as the first uplink channel.

The UEs 115 may transmit first uplink communications on the selectedfirst uplink channels during the second time period 680. For example,the first UE (UE0) may transmit a first uplink communication 630 on thesecond channel, the second UE (UE1) may transmit a first uplinkcommunication 635 on the first channel, and the third UE (UE2) maytransmit a first uplink communication 640 on the third channel.

The base station 105 may transmit second downlink data on one or more ofthe first plurality of data channels during the third time period 685.The base station 105 may transmit the second downlink data based on thedownlink carriers identified and/or selected based on the first randomor pseudorandom frequency hopping procedure. For example, during thethird time period, the base station 105 may transmit second downlinkdata 645 for a first UE (UE0) on the first channel corresponding tohopping frequency 1, second downlink data 650 for a second UE (UE1) onthe second channel corresponding to hopping frequency 2, and seconddownlink data 655 for the third UE (UE2) on a third channelcorresponding to hopping frequency 3.

Each UE 115 may perform a third random or pseudorandom frequency hoppingprocedure within the first plurality of downlink carriers to select oneof the first plurality of downlink channels as a second uplink channelfor the fourth time period 690. In some examples, the UE 115 mayrandomly or pseudo-randomly select the second uplink channel from thefirst plurality of downlink carriers, as described above with respect toFIG. 3 . In some examples, the UE 115 may randomly or pseudo-randomlyselect a second permutation of the first plurality of downlink carriers,and then select the second uplink channel based at least in part on theselected second permutation, as described above with respect to FIG. 4 .In some examples, the UE 115 may randomly or pseudo-randomly select asecond primary channel as the second uplink channel, as described abovewith respect to FIG. 5 . The UE 115 may perform the third random orpseudorandom frequency hopping procedure using the same algorithm as theUE 115 used to perform the second random or pseudorandom frequencyhopping procedure.

For example, with reference to FIG. 6 , a first UE (UE0) may randomly orpseudo-randomly select the second channel corresponding to hoppingfrequency 2 as the second uplink channel. A second UE (UE1) may selectthe third channel corresponding to hopping frequency 3 as the seconduplink channel. A third UE (UE2) may select a first channelcorresponding to hopping frequency 1 as the second uplink channel.

The UEs 115 may transmit second uplink communications on the selectedsecond uplink channels during the fourth time period 690. For example,the first UE (UE0) may transmit a second uplink communication 660 on thesecond channel, the second UE (UE1) may transmit a second uplinkcommunication 665 on the third channel, and the third UE (UE2) maytransmit a second uplink communication 670 on the first channel.

FIG. 7 illustrates an example of a communication flow 700 in a wirelesscommunication system that supports nested frequency hopping for datatransmission in accordance with various aspects of the presentdisclosure. In some examples, the wireless communication system mayimplement aspects of wireless communications system 100.

The communication flow 700 illustrates downlink communications from abase station 705 to a UE 710 and uplink communications from the UE 710to the base station 705. The base station 705 and the UE 710 may beexamples of aspects of base station 105 and UE 115 as described withreference to FIG. 1 . The communication flow 700 may illustratecommunications within a first frame (e.g., an m-frame). The first framemay include a first time period corresponding to a first downlinksegment, a second time period corresponding to a first uplink segment, athird time period corresponding to a second downlink segment, and afourth time period corresponding to a second uplink segment.

The base station 705 transmits a reference signal 715 to the UE 710. Thereference signal 715 may be a DRS. The reference signal 715 may betransmitted on at least one anchor channel.

The UE 710 may perform a first frequency hopping procedure 720. Thefirst frequency hopping procedure 720 may be a random or pseudorandomfrequency hopping procedure. The UE 710 may identify a plurality ofdownlink carriers for the first frame (e.g., for time periodscorresponding to the downlink segments of the first frame) using thefirst frequency hopping procedure 720. The base station 705 may transmita first downlink communication 725 to the UE 710 on one of the pluralityof downlink carriers during the first time period of the first frame.The first downlink communication 725 may include TDM information for thesecond time period.

The UE 710 may perform a second frequency hopping procedure 730. Thesecond frequency hopping procedure 730 may be a random or pseudorandomfrequency hopping procedure and may be performed within the plurality ofdownlink carriers. The UE 710 may select one of the plurality ofdownlink carriers as a first uplink channel for the time period based atleast in part on the second frequency hopping procedure 730.

In some examples, the second frequency hopping procedure 730 may includerandomly or pseudo-randomly selecting one of the plurality of downlinkcarriers as the first uplink channel. In some examples, the secondfrequency hopping procedure 730 may include randomly or pseudo-randomlyselecting a permutation of the plurality of downlink carriers, andselecting the first uplink channel based at least in part on theselected permutation. In some examples, the second frequency hoppingprocedure 730 may include randomly or pseudo-randomly selecting aprimary channel as the first uplink channel. In some examples, the UE710 may select the first uplink channel from the plurality of downlinkcarriers based at least in part on a random or pseudorandom numbergenerator, a random or pseudorandom pattern, or the like.

The UE 710 may transmit a first uplink communication 735 to the basestation 705 during the second time period. In some examples, e.g., whenanother UE in the cell has selected the same first uplink channel, theUE 710 may transmit the first uplink communication 735 based at least inpart on the time division multiplexing information from the firstdownlink communication 725.

The base station 705 may transmit a second downlink communication 740 tothe UE 710 on one of the plurality of downlink carriers during the thirdtime period. The base station 705 may use the same assignments used forthe first time period, such that the second downlink communication 740is received on the same channel as the first downlink communication 725.The second downlink communication 740 may include TDM information forthe fourth time period.

The UE 710 may perform a third frequency hopping procedure 745. Thethird frequency hopping procedure 745 may be a random or pseudorandomfrequency hopping procedure and may be performed within the plurality ofdownlink carriers. The UE 710 may select one of the plurality ofdownlink carriers as a second uplink channel for the fourth time periodusing the third frequency hopping procedure 745. The third frequencyhopping procedure 745 may be the same selection procedure as the secondfrequency hopping procedure 730.

The UE 710 may transmit a second uplink communication 750 to the basestation 705. The UE 710 may transmit the second uplink communication 750on the selected second uplink channel during the fourth time period. Insome examples, e.g., when another UE in the cell has selected the samesecond uplink channel, the UE 710 may transmit the second uplinkcommunication 750 based at least in part on time division multiplexinginformation included in the second downlink communication 740.

In some examples, the first frame may include additional uplinksegments. In such examples, the UE 710 may perform a new frequencyhopping procedure for each of the additional uplink segments, asdescribed above with respect to third frequency hopping procedure 745.

FIG. 8 illustrates an example of a communication flow 800 in a wirelesscommunication system that supports nested frequency hopping for datatransmission in accordance with various aspects of the presentdisclosure. In some examples, the wireless communication system mayimplement aspects of wireless communications system 100.

The communication flow 800 illustrates communications downlinkcommunications from a base station 805 to a UE 810 and uplinkcommunications from the UE 810 to the base station 805. The base station805 and the UE 810 may be examples of aspects of base station 105 and UE115 as described with reference to FIG. 1 . The communication flow 800may illustrate communications over two frames (e.g., two m-frames). Thefirst frame may include a first time period corresponding to a downlinksegment and a second time period corresponding to an uplink segment. Thesecond frame may include a third time period corresponding to a downlinksegment and a fourth time period corresponding to an uplink segment.

The base station 805 transmits a first reference signal 815 to the UE810. The first reference signal 815 may be a DRS. The first referencesignal 815 may be transmitted on at least one anchor channel.

The UE 810 may perform a first frequency hopping procedure 820. Thefirst frequency hopping procedure 820 may be a random or pseudorandomfrequency hopping procedure. The UE 810 may identify a first pluralityof downlink carriers for the first frame (e.g., for time periodscorresponding to a downlink segment of the first frame) using the firstfrequency hopping procedure 820. The base station 805 may transmit afirst downlink communication to the UE 810 on one of the first pluralityof downlink carriers during the first time period. In some examples, thefirst downlink communication may include TDM information for the secondtime period.

The UE 810 may perform a second frequency hopping procedure 825. Thesecond frequency hopping procedure 825 may be a random or pseudorandomfrequency hopping procedure and may be performed within the firstplurality of downlink carriers. The UE 810 may select one of the firstplurality of downlink carriers as a first uplink channel for the secondtime period using the second frequency hopping procedure 825.

In some examples, the second frequency hopping procedure 825 may includerandomly or pseudo-randomly selecting one of the first plurality ofdownlink carriers as the first uplink channel. In some examples, thesecond frequency hopping procedure 825 may include randomly orpseudo-randomly selecting a permutation of the first plurality ofdownlink carriers, and selecting the first uplink channel based at leastin part on the selected permutation. In some examples, the secondfrequency hopping procedure 825 may include randomly or pseudo-randomlyselecting a primary channel as the first uplink channel. In someexamples, the UE 810 may select the first uplink channel from the firstplurality of downlink carriers based at least in part on a random orpseudorandom number generator, a random or pseudorandom pattern, or thelike.

The UE 810 may transmit a first uplink communication 830 to the basestation 805. The UE 810 may transmit the first uplink communication 830on the selected first uplink channel during the second time period. Insome examples, e.g., when another UE in the cell has selected the samefirst uplink channel, the UE 810 may transmit the first uplinkcommunication 830 based at least in part on time division multiplexinginformation included in the first time period.

At the start of the second frame, the base station 805 may transmit asecond reference signal 835 to the UE 810. The second reference signal835 may be a DRS. The second reference signal 835 may be transmitted onthe at least one anchor channel.

The UE 810 may perform a third frequency hopping procedure 840. Thethird frequency hopping procedure 840 may be a random or pseudorandomfrequency hopping procedure. The UE 810 may identify a second pluralityof downlink carriers for the second frame (e.g., for time periodscorresponding to a downlink segment of the second frame) using the thirdfrequency hopping procedure 840. The base station 805 may transmit asecond downlink communication to the UE 810 on one of the secondplurality of downlink carriers during the third time period. In someexamples, the second downlink communication may include TDM informationfor the fourth time period.

The UE 810 may perform a fourth frequency hopping procedure 845. Thefourth frequency hopping procedure 845 may be a random or pseudorandomfrequency hopping procedure and may be performed within the secondplurality of downlink carriers. The UE 810 may select one of the secondplurality of downlink carriers as a second uplink channel for the fourthtime period using the fourth frequency hopping procedure 845. The fourthfrequency hopping procedure 845 may be the same selection procedure asthe second frequency hopping procedure 825.

The UE 810 may transmit a second uplink communication 850 to the basestation 805. The UE 810 may transmit the second uplink communication 850on the selected second uplink channel during the fourth time period. Insome examples, e.g., when another UE in the cell has selected the samesecond uplink channel, the UE 810 may transmit the second uplinkcommunication 850 based at least in part on time division multiplexinginformation included in the second downlink communication.

FIG. 9 shows a block diagram 900 of a wireless device 905 that supportsnested frequency hopping for data transmission in accordance withaspects of the present disclosure. Wireless device 905 may be an exampleof aspects of a user equipment (UE) 115 as described herein. Wirelessdevice 905 may include receiver 910, UE communications manager 915, andtransmitter 920. Wireless device 905 may also include a processor. Eachof these components may be in communication with one another (e.g., viaone or more buses).

Receiver 910 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to nestedfrequency hopping for data transmission, etc.). Information may bepassed on to other components of the device 905. The receiver 910 may bean example of aspects of the transceiver 1235 described with referenceto FIG. 12 . The receiver 910 may utilize a single antenna or a set ofantennas.

UE communications manager 915 may be an example of aspects of the UEcommunications manager 1215 described with reference to FIG. 12 .

UE communications manager 915 and/or at least some of its varioussub-components may be implemented in hardware, software executed by aprocessor, firmware, or any combination thereof. If implemented insoftware executed by a processor, the functions of the UE communicationsmanager 915 and/or at least some of its various sub-components may beexecuted by a general-purpose processor, a digital signal processor(DSP), an application-specific integrated circuit (ASIC), afield-programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described in thepresent disclosure. The UE communications manager 915 and/or at leastsome of its various sub-components may be physically located at variouspositions, including being distributed such that portions of functionsare implemented at different physical locations by one or more physicaldevices. In some examples, UE communications manager 915 and/or at leastsome of its various sub-components may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In other examples, UE communications manager 915 and/or at least some ofits various sub-components may be combined with one or more otherhardware components, including but not limited to an I/O component, atransceiver, a network server, another computing device, one or moreother components described in the present disclosure, or a combinationthereof in accordance with various aspects of the present disclosure.

UE communications manager 915 may receive, by a wireless device, adiscovery reference signal on at least one anchor carrier, perform afirst random or pseudorandom frequency hopping procedure to identify aset of downlink carriers for a first time period, perform a secondrandom or pseudorandom frequency hopping procedure within the set ofdownlink carriers to select one of the set of downlink channels as anuplink channel for a second time period, and transmit an uplinkcommunication on the selected uplink channel during the second timeperiod.

Transmitter 920 may transmit signals generated by other components ofthe device 905. In some examples, the transmitter 920 may be collocatedwith a receiver 910 in a transceiver module. For example, thetransmitter 920 may be an example of aspects of the transceiver 1235described with reference to FIG. 12 . The transmitter 920 may utilize asingle antenna or a set of antennas.

FIG. 10 shows a block diagram 1000 of a wireless device 1005 thatsupports nested frequency hopping for data transmission in accordancewith aspects of the present disclosure. Wireless device 1005 may be anexample of aspects of a wireless device 905 or a UE 115 as describedwith reference to FIG. 9 . Wireless device 1005 may include receiver1010, UE communications manager 1015, and transmitter 1020. Wirelessdevice 1005 may also include a processor. Each of these components maybe in communication with one another (e.g., via one or more buses).

Receiver 1010 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to nestedfrequency hopping for data transmission, etc.). Information may bepassed on to other components of the device 1005. The receiver 1010 maybe an example of aspects of the transceiver 1235 described withreference to FIG. 12 . The receiver 1010 may utilize a single antenna ora set of antennas.

UE communications manager 1015 may be an example of aspects of the UEcommunications manager 1215 described with reference to FIG. 12 .

UE communications manager 1015 may also include DRS processor 1025,first frequency hopping unit 1030, second frequency hopping unit 1035,and uplink communication channel selector 1040.

DRS processor 1025 may receive, by a wireless device, a discoveryreference signal on at least one anchor carrier and receive, by thewireless device, a second discovery reference signal on the at least oneanchor channel.

First frequency hopping unit 1030 may perform a first random orpseudorandom frequency hopping procedure to identify a set of downlinkcarriers for a first time period and perform a third random orpseudorandom frequency hopping procedure to identify a second set ofdownlink carriers for a third time period. In some cases, each of theset of downlink carriers includes a resource block.

Second frequency hopping unit 1035 may perform a second random orpseudorandom frequency hopping procedure within the set of downlinkcarriers to select one of the set of downlink channels as an uplinkchannel for a second time period, receive a downlink communication forthe wireless device on a downlink channel of the set of downlinkcarriers, where the uplink channel is different than the downlinkchannel, select the uplink channel based on the permutation, perform athird random or pseudorandom frequency hopping procedure within the setof downlink carriers to select a second one of the set of downlinkchannels as a second uplink channel for a third time period, and performa fourth random or pseudorandom frequency hopping procedure within theset of downlink carriers to select one of the second set of downlinkchannels as a second uplink channel for a fourth time period. In somecases, performing the second random or pseudo-random frequency hoppingprocedure within the set of downlink carriers includes: randomly orpseudo-randomly selecting the one of the set of downlink channels. Insome cases, performing the second random or pseudo-random frequencyhopping procedure within the set of downlink carriers includes: randomlyor pseudo-randomly selecting a permutation of the set of downlinkcarriers. In some cases, performing the second random or pseudo-randomfrequency hopping within the set of downlink carriers includes: randomlyor pseudo-randomly selecting a primary channel as the uplink channel. Insome cases, performing the second random or pseudo-random frequencyhopping procedure within the set of downlink carriers includes:selecting the one of the set of downlink carriers based on a random orpseudo-random number generator. In some cases, performing the secondrandom or pseudo-random frequency hopping procedure within the set ofdownlink carriers includes: selecting one of the set of data channelsbased on a random or pseudo-random hopping pattern.

Uplink communication channel selector 1040 may transmit an uplinkcommunication on the selected uplink channel during the second timeperiod, transmit a second uplink communication on the selected seconduplink channel during the third time period, where the third time periodis in the same frame, and transmit a second uplink communication on theselected second uplink channel during the fourth time period, where thefirst time period and the second time period are in a different framethan the third time period and the fourth time period. In some cases,the first time period and the second time period are in a same frame.

Transmitter 1020 may transmit signals generated by other components ofthe device 1005. In some examples, the transmitter 1020 may becollocated with a receiver 1010 in a transceiver module. For example,the transmitter 1020 may be an example of aspects of the transceiver1235 described with reference to FIG. 12 . The transmitter 1020 mayutilize a single antenna or a set of antennas.

FIG. 11 shows a block diagram 1100 of a UE communications manager 1115that supports nested frequency hopping for data transmission inaccordance with aspects of the present disclosure. The UE communicationsmanager 1115 may be an example of aspects of a UE communications manager915, a UE communications manager 1015, or a UE communications manager1215 described with reference to FIGS. 9, 10, and 12 . The UEcommunications manager 1115 may include DRS processor 1120, firstfrequency hopping unit 1125, second frequency hopping unit 1130, uplinkcommunication channel selector 1135, TDM processor 1140, and TDMscheduler 1145. Each of these modules may communicate, directly orindirectly, with one another (e.g., via one or more buses).

DRS processor 1120 may receive, by a wireless device, a discoveryreference signal on at least one anchor carrier and receive, by thewireless device, a second discovery reference signal on the at least oneanchor channel.

First frequency hopping unit 1125 may perform a first random orpseudorandom frequency hopping procedure to identify a set of downlinkcarriers for a first time period and perform a third random orpseudorandom frequency hopping procedure to identify a second set ofdownlink carriers for a third time period. In some cases, each of theset of downlink carriers includes a resource block.

Second frequency hopping unit 1130 may perform a second random orpseudorandom frequency hopping procedure within the set of downlinkcarriers to select one of the set of downlink channels as an uplinkchannel for a second time period, receive a downlink communication forthe wireless device on a downlink channel of the set of downlinkcarriers, where the uplink channel is different than the downlinkchannel, select the uplink channel based on the permutation, perform athird random or pseudorandom frequency hopping procedure within the setof downlink carriers to select a second one of the set of downlinkchannels as a second uplink channel for a third time period, and performa fourth random or pseudorandom frequency hopping procedure within theset of downlink carriers to select one of the second set of downlinkchannels as a second uplink channel for a fourth time period. In somecases, performing the second random or pseudo-random frequency hoppingprocedure within the set of downlink carriers includes: randomly orpseudo-randomly selecting the one of the set of downlink channels. Insome cases, performing the second random or pseudo-random frequencyhopping procedure within the set of downlink carriers includes: randomlyor pseudo-randomly selecting a permutation of the set of downlinkcarriers. In some cases, performing the second random or pseudo-randomfrequency hopping within the set of downlink carriers includes: randomlyor pseudo-randomly selecting a primary channel as the uplink channel. Insome cases, performing the second random or pseudo-random frequencyhopping procedure within the set of downlink carriers includes:selecting the one of the set of downlink carriers based on a random orpseudo-random number generator. In some cases, performing the secondrandom or pseudo-random frequency hopping procedure within the set ofdownlink carriers includes: selecting one of the set of data channelsbased on a random or pseudo-random hopping pattern.

Uplink communication channel selector 1135 may transmit an uplinkcommunication on the selected uplink channel during the second timeperiod, transmit a second uplink communication on the selected seconduplink channel during the third time period, where the third time periodis in the same frame, and transmit a second uplink communication on theselected second uplink channel during the fourth time period, where thefirst time period and the second time period are in a different framethan the third time period and the fourth time period. In some cases,the first time period and the second time period are in a same frame.

TDM processor 1140 may receive, from a base station, time divisionmultiplexing information for the uplink channel.

TDM scheduler 1145 may schedule transmission of uplink communications ona channel. In some cases, the uplink communication is transmitted basedon the time division multiplexing information.

FIG. 12 shows a diagram of a system 1200 including a device 1205 thatsupports nested frequency hopping for data transmission in accordancewith aspects of the present disclosure. Device 1205 may be an example ofor include the components of wireless device 905, wireless device 1005,or a UE 115 as described above, e.g., with reference to FIGS. 9 and 10 .Device 1205 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, including UE communications manager 1215, processor1220, memory 1225, software 1230, transceiver 1235, antenna 1240, andI/O controller 1245. These components may be in electronic communicationvia one or more buses (e.g., bus 1210). Device 1205 may communicatewirelessly with one or more base stations 105.

Processor 1220 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a central processing unit (CPU), amicrocontroller, an ASIC, an FPGA, a programmable logic device, adiscrete gate or transistor logic component, a discrete hardwarecomponent, or any combination thereof). In some cases, processor 1220may be configured to operate a memory array using a memory controller.In other cases, a memory controller may be integrated into processor1220. Processor 1220 may be configured to execute computer-readableinstructions stored in a memory to perform various functions (e.g.,functions or tasks supporting nested frequency hopping for datatransmission).

Memory 1225 may include random access memory (RAM) and read only memory(ROM). The memory 1225 may store computer-readable, computer-executablesoftware 1230 including instructions that, when executed, cause theprocessor to perform various functions described herein. In some cases,the memory 1225 may contain, among other things, a basic input/outputsystem (BIOS) which may control basic hardware or software operationsuch as the interaction with peripheral components or devices.

Software 1230 may include code to implement aspects of the presentdisclosure, including code to support nested frequency hopping for datatransmission. Software 1230 may be stored in a non-transitorycomputer-readable medium such as system memory or other memory. In somecases, the software 1230 may not be directly executable by the processorbut may cause a computer (e.g., when compiled and executed) to performfunctions described herein.

Transceiver 1235 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1235 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1235 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device 1205 may include a single antenna1240. However, in some cases the device 1205 may have more than oneantenna 1240, which may be capable of concurrently transmitting orreceiving multiple wireless transmissions.

I/O controller 1245 may manage input and output signals for device 1205.I/O controller 1245 may also manage peripherals not integrated intodevice 1205. In some cases, I/O controller 1245 may represent a physicalconnection or port to an external peripheral. In some cases, I/Ocontroller 1245 may utilize an operating system such as iOS®, ANDROID®,MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operatingsystem. In other cases, I/O controller 1245 may represent or interactwith a modem, a keyboard, a mouse, a touchscreen, or a similar device.In some cases, I/O controller 1245 may be implemented as part of aprocessor. In some cases, a user may interact with device 1205 via I/Ocontroller 1245 or via hardware components controlled by I/O controller1245.

FIG. 13 shows a block diagram 1300 of a wireless device 1305 thatsupports nested frequency hopping for data transmission in accordancewith aspects of the present disclosure. Wireless device 1305 may be anexample of aspects of a base station 105 as described herein. Wirelessdevice 1305 may include receiver 1310, base station communicationsmanager 1315, and transmitter 1320. Wireless device 1305 may alsoinclude a processor. Each of these components may be in communicationwith one another (e.g., via one or more buses).

Receiver 1310 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to nestedfrequency hopping for data transmission, etc.). Information may bepassed on to other components of the device 1305. The receiver 1310 maybe an example of aspects of the transceiver 1635 described withreference to FIG. 16 . The receiver 1310 may utilize a single antenna ora set of antennas.

Receiver 1310 may receive the uplink transmissions over the selecteduplink channel during the second time period based on the time divisionmultiplexing information.

Base station communications manager 1315 may be an example of aspects ofthe base station communications manager 1615 described with reference toFIG. 16 .

Base station communications manager 1315 and/or at least some of itsvarious sub-components may be implemented in hardware, software executedby a processor, firmware, or any combination thereof. If implemented insoftware executed by a processor, the functions of the base stationcommunications manager 1315 and/or at least some of its varioussub-components may be executed by a general-purpose processor, a DSP, anASIC, an FPGA or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described in the presentdisclosure. The base station communications manager 1315 and/or at leastsome of its various sub-components may be physically located at variouspositions, including being distributed such that portions of functionsare implemented at different physical locations by one or more physicaldevices. In some examples, base station communications manager 1315and/or at least some of its various sub-components may be a separate anddistinct component in accordance with various aspects of the presentdisclosure. In other examples, base station communications manager 1315and/or at least some of its various sub-components may be combined withone or more other hardware components, including but not limited to anI/O component, a transceiver, a network server, another computingdevice, one or more other components described in the presentdisclosure, or a combination thereof in accordance with various aspectsof the present disclosure.

Base station communications manager 1315 may transmit, by a wirelessdevice, a discovery reference signal on at least three anchor carriers,perform a first random or pseudorandom frequency hopping procedure toselect a set of downlink carriers for a first time period, identify ananticipated collision of uplink transmissions from user equipment (UEs)during a second time period based on a second random or pseudorandomfrequency hopping procedure within the set of downlink carriers, andtransmit time division multiplexing information for the second timeperiod to the UEs.

Transmitter 1320 may transmit signals generated by other components ofthe device 1305. In some examples, the transmitter 1320 may becollocated with a receiver 1310 in a transceiver module. For example,the transmitter 1320 may be an example of aspects of the transceiver1635 described with reference to FIG. 16 . The transmitter 1320 mayutilize a single antenna or a set of antennas.

FIG. 14 shows a block diagram 1400 of a wireless device 1405 thatsupports nested frequency hopping for data transmission in accordancewith aspects of the present disclosure. Wireless device 1405 may be anexample of aspects of a wireless device 1305 or a base station 105 asdescribed with reference to FIG. 13 . Wireless device 1405 may includereceiver 1410, base station communications manager 1415, and transmitter1420. Wireless device 1405 may also include a processor. Each of thesecomponents may be in communication with one another (e.g., via one ormore buses).

Receiver 1410 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to nestedfrequency hopping for data transmission, etc.). Information may bepassed on to other components of the device 1405. The receiver 1410 maybe an example of aspects of the transceiver 1635 described withreference to FIG. 16 . The receiver 1410 may utilize a single antenna ora set of antennas.

Base station communications manager 1415 may be an example of aspects ofthe base station communications manager 1615 described with reference toFIG. 16 .

Base station communications manager 1415 may also include DRStransmission unit 1425, frequency hopping unit 1430, anticipatedcollision identifier 1435, and TDM transmitter 1440.

DRS transmission unit 1425 may transmit, by a wireless device, adiscovery reference signal on at least three anchor carriers.

Frequency hopping unit 1430 may perform a first random or pseudorandomfrequency hopping procedure to select a set of downlink carriers for afirst time period.

Anticipated collision identifier 1435 may identify an anticipatedcollision of uplink transmissions from user equipment (UEs) during asecond time period based on a second random or pseudorandom frequencyhopping procedure within the set of downlink carriers.

TDM transmitter 1440 may transmit time division multiplexing informationfor the second time period to the UEs and transmit a downlinkcommunication on at least one of the set of downlink carriers, where thedownlink communication includes the time division multiplexinginformation.

Transmitter 1420 may transmit signals generated by other components ofthe device 1405. In some examples, the transmitter 1420 may becollocated with a receiver 1410 in a transceiver module. For example,the transmitter 1420 may be an example of aspects of the transceiver1635 described with reference to FIG. 16 . The transmitter 1420 mayutilize a single antenna or a set of antennas.

FIG. 15 shows a block diagram 1500 of a base station communicationsmanager 1515 that supports nested frequency hopping for datatransmission in accordance with aspects of the present disclosure. Thebase station communications manager 1515 may be an example of aspects ofa base station communications manager 1615 described with reference toFIGS. 13, 14, and 16 . The base station communications manager 1515 mayinclude DRS transmission unit 1520, frequency hopping unit 1525,anticipated collision identifier 1530, and TDM transmitter 1535. Each ofthese modules may communicate, directly or indirectly, with one another(e.g., via one or more buses).

DRS transmission unit 1520 may transmit, by a wireless device, adiscovery reference signal on at least three anchor carriers.

Frequency hopping unit 1525 may perform a first random or pseudorandomfrequency hopping procedure to select a set of downlink carriers for afirst time period.

Anticipated collision identifier 1530 may identify an anticipatedcollision of uplink transmissions from user equipment (UEs) during asecond time period based on a second random or pseudorandom frequencyhopping procedure within the set of downlink carriers.

TDM transmitter 1535 may transmit time division multiplexing informationfor the second time period to the UEs and transmit a downlinkcommunication on at least one of the set of downlink carriers, where thedownlink communication includes the time division multiplexinginformation.

FIG. 16 shows a diagram of a system 1600 including a device 1605 thatsupports nested frequency hopping for data transmission in accordancewith aspects of the present disclosure. Device 1605 may be an example ofor include the components of base station 105 as described above, e.g.,with reference to FIG. 1 . Device 1605 may include components forbi-directional voice and data communications including components fortransmitting and receiving communications, including base stationcommunications manager 1615, processor 1620, memory 1625, software 1630,transceiver 1635, antenna 1640, network communications manager 1645, andinter-station communications manager 1650. These components may be inelectronic communication via one or more buses (e.g., bus 1610). Device1605 may communicate wirelessly with one or more UEs 115.

Processor 1620 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, processor 1620 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into processor 1620. Processor 1620 may be configured toexecute computer-readable instructions stored in a memory to performvarious functions (e.g., functions or tasks supporting nested frequencyhopping for data transmission).

Memory 1625 may include RAM and ROM. The memory 1625 may storecomputer-readable, computer-executable software 1630 includinginstructions that, when executed, cause the processor to perform variousfunctions described herein. In some cases, the memory 1625 may contain,among other things, a BIOS which may control basic hardware or softwareoperation such as the interaction with peripheral components or devices.

Software 1630 may include code to implement aspects of the presentdisclosure, including code to support nested frequency hopping for datatransmission. Software 1630 may be stored in a non-transitorycomputer-readable medium such as system memory or other memory. In somecases, the software 1630 may not be directly executable by the processorbut may cause a computer (e.g., when compiled and executed) to performfunctions described herein.

Transceiver 1635 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1635 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1635 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device 1605 may include a single antenna1640. However, in some cases the device may have more than one antenna1640, which may be capable of concurrently transmitting or receivingmultiple wireless transmissions.

Network communications manager 1645 may manage communications with thecore network (e.g., via one or more wired backhaul links). For example,the network communications manager 1645 may manage the transfer of datacommunications for client devices, such as one or more UEs 115.

Inter-station communications manager 1650 may manage communications withother base station 105, and may include a controller or scheduler forcontrolling communications with UEs 115 in cooperation with other basestations 105. For example, the inter-station communications manager 1650may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, inter-station communications manager1650 may provide an X2 interface within an Long Term Evolution(LTE)/LTE-A wireless communication network technology to providecommunication between base stations 105.

FIG. 17 shows a flowchart illustrating a method 1700 for nestedfrequency hopping for data transmission in accordance with aspects ofthe present disclosure. The operations of method 1700 may be implementedby a UE 115 or its components as described herein. For example, theoperations of method 1700 may be performed by a UE communicationsmanager as described with reference to FIGS. 9 through 12 . In someexamples, a UE 115 may execute a set of codes to control the functionalelements of the device to perform the functions described below.Additionally or alternatively, the UE 115 may perform aspects of thefunctions described below using special-purpose hardware.

At 1705, the UE 115 may receive, by a wireless device, a discoveryreference signal on at least one anchor carrier. The operations of 1705may be performed according to the methods described herein. In certainexamples, aspects of the operations of 1705 may be performed by a DRSprocessor as described with reference to FIGS. 9 through 12 .

At 1710, the UE 115 may perform a first random or pseudorandom frequencyhopping procedure to identify a plurality of downlink carriers for afirst time period. The operations of 1710 may be performed according tothe methods described herein. In certain examples, aspects of theoperations of 1710 may be performed by a first frequency hopping unit asdescribed with reference to FIGS. 9 through 12 .

At 1715, the UE 115 may perform a second random or pseudorandomfrequency hopping procedure within the plurality of downlink carriers toselect one of the plurality of downlink channels as an uplink channelfor a second time period. The operations of 1715 may be performedaccording to the methods described herein. In certain examples, aspectsof the operations of 1715 may be performed by a second frequency hoppingunit as described with reference to FIGS. 9 through 12 .

At 1720, the UE 115 may transmit an uplink communication on the selecteduplink channel during the second time period. The operations of 1720 maybe performed according to the methods described herein. In certainexamples, aspects of the operations of 1720 may be performed by anuplink communication channel selector as described with reference toFIGS. 9 through 12 .

FIG. 18 shows a flowchart illustrating a method 1800 for nestedfrequency hopping for data transmission in accordance with aspects ofthe present disclosure. The operations of method 1800 may be implementedby a base station 105 or its components as described herein. Forexample, the operations of method 1800 may be performed by a basestation communications manager as described with reference to FIGS. 13through 16 . In some examples, a base station 105 may execute a set ofcodes to control the functional elements of the device to perform thefunctions described below. Additionally or alternatively, the basestation 105 may perform aspects of the functions described below usingspecial-purpose hardware.

At 1805, the base station 105 may transmit, by a wireless device, adiscovery reference signal on at least three anchor carriers. Theoperations of 1805 may be performed according to the methods describedherein. In certain examples, aspects of the operations of 1805 may beperformed by a DRS transmission unit as described with reference toFIGS. 13 through 16 .

At 1810, the base station 105 may perform a first random or pseudorandomfrequency hopping procedure to select a plurality of downlink carriersfor a first time period. The operations of 1810 may be performedaccording to the methods described herein. In certain examples, aspectsof the operations of 1810 may be performed by a frequency hopping unitas described with reference to FIGS. 13 through 16 .

At 1815, the base station 105 may identify an anticipated collision ofuplink transmissions from user equipment (UEs) during a second timeperiod based at least in part on a second random or pseudorandomfrequency hopping procedure within the plurality of downlink carriers.The operations of 1815 may be performed according to the methodsdescribed herein. In certain examples, aspects of the operations of 1815may be performed by an anticipated collision identifier as describedwith reference to FIGS. 13 through 16 .

At 1820, the base station 105 may transmit time division multiplexinginformation for the second time period to the UEs. The operations of1820 may be performed according to the methods described herein. Incertain examples, aspects of the operations of 1820 may be performed bya TDM transmitter as described with reference to FIGS. 13 through 16 .

It should be noted that the methods described above describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.A CDMA system may implement a radio technology such as CDMA2000,Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000,IS-95, and IS-856 standards. IS-2000 Releases may be commonly referredto as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releasesof UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR,and GSM are described in documents from the organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned above as well as other systemsand radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NRsystem may be described for purposes of example, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, thetechniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro,or NR applications.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEs115 with service subscriptions with the network provider. A small cellmay be associated with a lower-powered base station 105, as comparedwith a macro cell, and a small cell may operate in the same or different(e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Smallcells may include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs 115 with servicesubscriptions with the network provider. A femto cell may also cover asmall geographic area (e.g., a home) and may provide restricted accessby UEs 115 having an association with the femto cell (e.g., UEs 115 in aclosed subscriber group (CSG), UEs 115 for users in the home, and thelike). An eNB for a macro cell may be referred to as a macro eNB. An eNBfor a small cell may be referred to as a small cell eNB, a pico eNB, afemto eNB, or a home eNB. An eNB may support one or multiple (e.g., two,three, four, and the like) cells, and may also support communicationsusing one or multiple component carriers.

The wireless communications system 100 or systems described herein maysupport synchronous or asynchronous operation. For synchronousoperation, the base stations 105 may have similar frame timing, andtransmissions from different base stations 105 may be approximatelyaligned in time. For asynchronous operation, the base stations 105 mayhave different frame timing, and transmissions from different basestations 105 may not be aligned in time. The techniques described hereinmay be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a digital signal processor (DSP), anapplication-specific integrated circuit (ASIC), a field-programmablegate array (FPGA) or other programmable logic device (PLD), discretegate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude random-access memory (RAM), read-only memory (ROM), electricallyerasable programmable read only memory (EEPROM), flash memory, compactdisk (CD) ROM or other optical disk storage, magnetic disk storage orother magnetic storage devices, or any other non-transitory medium thatcan be used to carry or store desired program code means in the form ofinstructions or data structures and that can be accessed by ageneral-purpose or special-purpose computer, or a general-purpose orspecial-purpose processor. Also, any connection is properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. Disk and disc, as used herein, include CD, laserdisc, optical disc, digital versatile disc (DVD), floppy disk andBlu-ray disc where disks usually reproduce data magnetically, whilediscs reproduce data optically with lasers. Combinations of the aboveare also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communication, comprising:transmitting, by a network device, a discovery reference signal toestablish a connection with one or more user equipment (UEs) on at leastthree anchor carriers; performing a first random or pseudorandomfrequency hopping procedure to select a plurality of downlink carriersfor a first time period; detecting an anticipated collision of uplinktransmissions from the one or more UEs during a second time period basedat least in part on a second random or pseudorandom frequency hoppingprocedure within the plurality of downlink carriers; transmitting, tothe one or more UEs, time division multiplexing information to multiplexthe uplink transmissions from the one or more UEs on a same hoppingfrequency during the second time period; and receiving the uplinktransmissions over an uplink channel selected from the plurality ofdownlink carriers during the second time period based at least in parton the time division multiplexing information.
 2. The method of claim 1,further comprising: transmitting a downlink communication on at leastone of the plurality of downlink carriers, wherein the downlinkcommunication comprises the time division multiplexing information. 3.The method of claim 1, wherein the first time period and the second timeperiod are in a same frame.
 4. The method of claim 3, furthercomprising: transmitting a second discovery reference signal on the atleast three anchor carriers; and receiving a second uplink communicationon a second uplink channel during a third time period, wherein the firsttime period and the second time period are in a different frame than thethird time period.
 5. The method of claim 4, further comprising:receiving a third uplink communication on the second uplink channelduring a fourth time period, wherein the first time period and thesecond time period are in a different frame than the third time periodand the fourth time period.
 6. The method of claim 1, wherein thediscovery reference signal is transmitted in accordance with a thresholdtransmission power on the at least three anchor carriers.
 7. The methodof claim 1, wherein each of the plurality of downlink carriers comprisesa resource block.
 8. An apparatus for wireless communication,comprising: a processor; memory coupled with the processor; andinstructions stored in the memory and executable by the processor tocause the apparatus to: transmit, by a network device, a discoveryreference signal to establish a connection with one or more userequipment (UEs) on at least three anchor carriers; perform a firstrandom or pseudorandom frequency hopping procedure to select a pluralityof downlink carriers for a first time period; detect an anticipatedcollision of uplink transmissions from the one or more UEs during asecond time period based at least in part on a second random orpseudorandom frequency hopping procedure within the plurality ofdownlink carriers; transmit, to the one or more UEs, time divisionmultiplexing information to multiplex the uplink transmissions from theone or more UEs on a same hopping frequency during the second timeperiod; and receive the uplink transmissions over an uplink channelselected from the plurality of downlink carriers during the second timeperiod based at least in part on the time division multiplexinginformation.
 9. The apparatus of claim 8, wherein the instructions arefurther executable by the processor to cause the apparatus to: transmita downlink communication on at least one of the plurality of downlinkcarriers, wherein the downlink communication comprises the time divisionmultiplexing information.
 10. The apparatus of claim 8, wherein thefirst time period and the second time period are in a same frame. 11.The apparatus of claim 10, wherein the instructions are furtherexecutable by the processor to cause the apparatus to: transmit a seconddiscovery reference signal on the at least three anchor carriers; andreceive a second uplink communication on a second uplink channel duringa third time period, wherein the first time period and the second timeperiod are in a different frame than the third time period.
 12. Theapparatus of claim 11, wherein the instructions are further executableby the processor to cause the apparatus to: receive a third uplinkcommunication on the second uplink channel during a fourth time period,wherein the first time period and the second time period are in adifferent frame than the third time period and the fourth time period.13. The apparatus of claim 8, wherein the discovery reference signal istransmitted in accordance with a threshold transmission power on the atleast three anchor carriers.
 14. The apparatus of claim 8, wherein eachof the plurality of downlink carriers comprises a resource block.
 15. Anapparatus for wireless communication, comprising: means fortransmitting, by a network device, a discovery reference signal toestablish a connection with one or more user equipment (UEs) on at leastthree anchor carriers; means for performing a first random orpseudorandom frequency hopping procedure to select a plurality ofdownlink carriers for a first time period; means for detecting ananticipated collision of uplink transmissions from the one or more UEsduring a second time period based at least in part on a second random orpseudorandom frequency hopping procedure within the plurality ofdownlink carriers; means for transmitting, to the one or more UEs, timedivision multiplexing information to multiplex the uplink transmissionsfrom the one or more UEs on a same hopping frequency during the secondtime period; and means for receiving the uplink transmissions over anuplink channel selected from the plurality of downlink carriers duringthe second time period based at least in part on the time divisionmultiplexing information.
 16. The apparatus of claim 15, furthercomprising: means for transmitting a downlink communication on at leastone of the plurality of downlink carriers, wherein the downlinkcommunication comprises the time division multiplexing information. 17.The apparatus of claim 15, wherein the first time period and the secondtime period are in a same frame.
 18. The apparatus of claim 17, furthercomprising: means for transmitting a second discovery reference signalon the at least three anchor carriers; and means for receiving a seconduplink communication on a second uplink channel during a third timeperiod, wherein the first time period and the second time period are ina different frame than the third time period.
 19. The apparatus of claim18, further comprising: means for receiving a third uplink communicationon the second uplink channel during a fourth time period, wherein thefirst time period and the second time period are in a different framethan the third time period and the fourth time period.
 20. The apparatusof claim 15, wherein the discovery reference signal is transmitted inaccordance with a threshold transmission power on the at least threeanchor carriers.
 21. The apparatus of claim 15, wherein each of theplurality of downlink carriers comprises a resource block.
 22. Anon-transitory computer-readable medium storing code for wirelesscommunication, the code comprising instructions executable by aprocessor to: transmit, by a network device, a discovery referencesignal to establish a connection with one or more user equipment (UEs)on at least three anchor carriers; perform a first random orpseudorandom frequency hopping procedure to select a plurality ofdownlink carriers for a first time period; detect an anticipatedcollision of uplink transmissions from the one or more UEs during asecond time period based at least in part on a second random orpseudorandom frequency hopping procedure within the plurality ofdownlink carriers; transmit, to the one or more UEs, time divisionmultiplexing information to multiplex the uplink transmissions from theone or more UEs on a same hopping frequency during the second timeperiod; and receive the uplink transmissions over an uplink channelselected from the plurality of downlink carriers during the second timeperiod based at least in part on the time division multiplexinginformation.
 23. The non-transitory computer-readable medium of claim22, wherein the instructions are further executable by the processor to:transmit a downlink communication on at least one of the plurality ofdownlink carriers, wherein the downlink communication comprises the timedivision multiplexing information.
 24. The non-transitorycomputer-readable medium of claim 22, wherein the first time period andthe second time period are in a same frame.
 25. The non-transitorycomputer-readable medium of claim 24, wherein the instructions arefurther executable by the processor to: transmit a second discoveryreference signal on the at least three anchor carriers; and receive asecond uplink communication on a second uplink channel during a thirdtime period, wherein the first time period and the second time periodare in a different frame than the third time period.
 26. Thenon-transitory computer-readable medium of claim 25, wherein theinstructions are further executable by the processor to: receive a thirduplink communication on the second uplink channel during a fourth timeperiod, wherein the first time period and the second time period are ina different frame than the third time period and the fourth time period.